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Sustiva


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Summary for the public


What is Sustiva?

Sustiva is a medicine that contains the active substance efavirenz. It is available as capsules (yellow and white: 50 mg; white: 100 mg; yellow: 200 mg), as yellow, capsule-shaped tablets (600 mg) and as an oral solution (30 mg/ml).


What is Sustiva used for?

Sustiva is an antiviral medicine. It is used together with other antiviral medicines to treat adults and children aged three years or older infected with human immunodeficiency virus type 1 (HIV-1), a virus that causes acquired immune deficiency syndrome (AIDS).

The medicine can only be obtained with a prescription.


How is Sustiva used?

Treatment with Sustiva should be started by a doctor who has experience in the management of HIV infection. Sustiva must be given in combination with other antiviral medicines. It is recommended that Sustiva be taken on an empty stomach and without food, preferably at bedtime.

The recommended dose of Sustiva for adults is 600 mg once a day. In patients aged three to 17 years, the dose depends on body weight. For patients who are unable to swallow the capsules or tablets, Sustiva can be given using the oral solution. If the patient cannot tolerate the oral solution, mixing the contents of the capsules with a small amount of food (around two teaspoons) can be considered. The dose of Sustiva needs to be reduced in patients taking voriconazole (used to treat fungal infections). Patients taking rifampicin (an antibiotic) may need to take a higher dose of Sustiva.

For full details, see the Summary of Product Characteristics (also part of the EPAR).


How does Sustiva work?

The active substance in Sustiva, efavirenz, is a non-nucleoside reverse transcriptase inhibitor (NNRTI). It blocks the activity of reverse transcriptase, an enzyme produced by HIV that allows it to infect cells in the body and make more viruses. By blocking this enzyme, Sustiva, taken in combination with other antiviral medicines, reduces the amount of HIV in the blood and keeps it at a low level. Sustiva does not cure HIV infection or AIDS, but it may delay the damage to the immune system and the development of infections and diseases associated with AIDS.


How has Sustiva been studied?

Sustiva has been studied in three main studies involving over 1,100 adults:

  • in the first study, Sustiva in combination with lamivudine and zidovudine or with indinavir (other antiviral medicines) was compared with the combination of indinavir, lamivudine and zidovudine;
  • the second study compared Sustiva in combination with nelfinavir and two other antiviral medicines with the same combination without Sustiva;
  • the third study compared adding Sustiva or placebo (a dummy treatment) to a combination of antiviral medicines that included indinavir and two other antiviral medicines, in patients who had already been receiving treatment for HIV infection.

Sustiva has also been studied in 57 children aged between three and 16 years, in combination with nelfinavir and other antiviral medicines.


What benefit has Sustiva shown during the studies?

All of the studies showed that combinations including Sustiva were at least as effective as the comparator medicines:

  • the first study showed that 67% of the adults treated with Sustiva in combination with zidovudine and lamivudine had viral loads below 400 copies/ml after 48 weeks, compared with 54% of the patients treated with Sustiva and indinavir, and 45% of the patients treated with indinavir, lamivudine and zidovudine;
  • in the second study, Sustiva in combination with nelfinavir was superior to the combination without Sustiva: 70% and 30% of the patients, respectively, had viral loads below 500 copies/ml after 48 weeks;
  • the third study showed that more patients receiving Sustiva had viral loads below 400 copies/ml than those taking placebo after 24 weeks.

Similar results were seen in the study in children.


What is the risk associated with Sustiva?

The most common side effect with Sustiva (seen in more than 1 patient in 10) is rash. Sustiva is also associated with nervous system symptoms, such as dizziness, insomnia (difficulty sleeping), somnolence (sleepiness), impaired concentration and abnormal dreaming, and with psychiatric disorders, including severe depression, suicidal thoughts, suicide attempts and aggressive behaviour, especially in patients with a history of mental illness. Taking Sustiva with food may lead to an increase in the frequency of side effects. For a more complete list of side effects reported with Sustiva, see the Package Leaflet.

Sustiva should not be used in patients who may be hypersensitive (allergic) to efavirenz or any of the other ingredients. It must not be used in patients with severe liver disease or who are taking any of the following medicines:

  • astemizole, terfenadine (commonly used to treat allergy symptoms - these medicines may be available without prescription);
  • dihydroergotamine, ergotamine, ergonovine, methylergonovine (used to treat migraine headache);
  • midazolam, triazolam (used to relieve anxiety or difficulty sleeping);
  • pimozide (used to treat mental illnesses);
  • cisapride (used to relieve certain stomach problems);
  • bepridil (used to treat angina);
  • St John’s wort (a herbal preparation used to treat depression).

Caution is also needed when Sustiva is taken at the same time as other medicines. See the Package Leaflet for further details.

As with other anti-HIV medicines, patients taking Sustiva may be at risk of lipodystrophy (changes in the distribution of body fat), osteonecrosis (death of bone tissue) or immune reactivation syndrome (symptoms of infection caused by the recovering immune system). Patients who have problems with their liver (including hepatitis B or C infection) may be at an elevated risk of liver damage when taking Sustiva.


Why has Sustiva been approved?

The Committee for Medicinal Products for Human Use (CHMP) decided that Sustiva’s benefits are greater than its risks in antiviral combination treatment of HIV-infected adults, adolescents and children three years of age and older. The Committee noted that Sustiva has not been studied adequately in patients with advanced disease (CD4 cell counts below 50 cells/mm3) or after treatment with protease inhibitors (another type of antiviral medicine) that was not working. The Committee also noted that there is little information on the benefits of treatment including a protease inhibitor in patients who have been treated with Sustiva in the past but which stopped working, although there is no evidence to suggest that protease inhibitors may not work in these patients. The Committee recommended that Sustiva be given marketing authorisation.


Other information about Sustiva:

The European Commission granted a marketing authorisation valid throughout the European Union for Sustiva on 28 May 1999. The marketing authorisation holder is Bristol-Myers Squibb Pharma EEIG. The marketing authorisation was renewed on 28 May 2004 and on 28 May 2009.

Authorisation details
Name: Sustiva
EMEA Product number: EMEA/H/C/000249
Active substance: efavirenz
INN or common name: efavirenz
Therapeutic area: HIV Infections
ATC Code: J05AG03
Marketing Authorisation Holder: Bristol-Myers Squibb Pharma EEIG
Revision: 28
Date of issue of Market Authorisation valid throughout the European Union: 28/05/1999
Contact address:
Bristol-Myers Squibb Pharma EEIG
Uxbridge Business Park
Sanderson Road
Uxbridge UB8 1DH
United Kingdom




Product Characteristics

ANNEX I

SUMMARY OF PRODUCT CHARACTERISTICS


1.
NAME OF THE MEDICINAL PRODUCT
SUSTIVA 50 mg hard capsules
2.
QUALITATIVE AND QUANTITATIVE COMPOSITION
Each hard capsule contains 50 mg of efavirenz.
Excipient: each hard capsule contains 28.5 mg of lactose monohydrate.
For a full list of excipients, see section 6.1.
3.
PHARMACEUTICAL FORM
Hard capsule
Dark yellow and white, printed with "SUSTIVA" on the dark yellow cap and "50 mg" on the white
body.
4.
CLINICAL PARTICULARS
4.1 Therapeutic indications
SUSTIVA is indicated in antiviral combination treatment of human immunodeficiency virus-1
(HIV-1) infected adults, adolescents and children 3 years of age and older.
SUSTIVA has not been adequately studied in patients with advanced HIV disease, namely in patients
with CD4 counts < 50 cells/mm 3 , or after failure of protease inhibitor (PI) containing regimens.
Although cross-resistance of efavirenz with PIs has not been documented, there are at present
insufficient data on the efficacy of subsequent use of PI based combination therapy after failure of
regimens containing SUSTIVA.
For a summary of clinical and pharmacodynamic information, see section 5.1.
4.2 Posology and method of administration
Posology
Therapy should be initiated by a physician experienced in the management of HIV infection.
Concomitant antiretroviral therapy: SUSTIVA must be given in combination with other antiretroviral
medicines (see section 4.5).
It is recommended that SUSTIVA be taken on an empty stomach. The increased efavirenz
concentrations observed following administration of SUSTIVA with food may lead to an increase in
frequency of adverse reactions (see sections 4.4. and 5.2).
In order to improve the tolerability of nervous system undesirable effects, bedtime dosing is
recommended (see section 4.8).
Adults: the recommended dose of SUSTIVA in combination with nucleoside analogue reverse
transcriptase inhibitors (NRTIs) with or without a PI (see section 4.5) is 600 mg orally, once daily.
2
Dose adjustment: If SUSTIVA is coadministered with voriconazole, the voriconazole maintenance
dose must be increased to 400 mg every 12 hours and the SUSTIVA dose must be reduced by 50%,
i.e., to 300 mg once daily. When treatment with voriconazole is stopped, the initial dose of efavirenz
should be restored (see section 4.5).
If SUSTIVA is coadministered with rifampicin, an increase in the dose of SUSTIVA to 800 mg/day
may be considered (see section 4.5).
Special populations
Renal impairment: the pharmacokinetics of efavirenz have not been studied in patients with renal
insufficiency; however, less than 1% of an efavirenz dose is excreted unchanged in the urine, so the
impact of renal impairment on efavirenz elimination should be minimal (see section 4.4).
Hepatic impairment: patients with mild liver disease may be treated with their normally recommended
dose of efavirenz. Patients should be monitored carefully for dose-related adverse reactions, especially
nervous system symptoms (see sections 4.3 and 4.4).
Paediatric population (3 to 17 years)
The recommended dose of SUSTIVA in combination with a PI and/or NRTIs for patients between 3
and 17 years of age is described in Table 1. SUSTIVA hard capsules must only be administered to
children who are able to reliably swallow hard capsules. The safety and efficacy of SUSTIVA in
children below the age of 3 years or weighing less than 13 kg have not yet been established (see
sections 5.1 and 5.2).
Alternative method of administration: for children at least 3 years old and weighing at least 13 kg and
adults who cannot reliably swallow hard capsules, SUSTIVA oral solution is the preferred
formulation. Administration of the capsule contents with a small amount (1-2 teaspoons) of food may
be considered for patients who cannot tolerate the oral solution. In a palatability study in healthy
adults of efavirenz mixed with applesauce, grape jelly, yogurt, or infant formula, grape jelly received
the highest rating of good overall taste. Patients and caregivers must be instructed to open the capsule
carefully to avoid spillage or dispersion of the capsule contents into the air. It is recommended to hold
the capsule vertically with the cap facing up and to pull the cap away from the body of the capsule,
and to mix the capsule contents with food in a small container. The mixture should be administered as
soon as possible, but no more than 30 minutes after mixing. After administration of the efavirenz-food
mixture, an additional small amount (approximately 2 teaspoons) of food must be added to the empty
mixing container, stirred to disperse any remaining residue of the medicinal product, and administered
to the patient. No additional food should be consumed for up to 2 hours after administration of
efavirenz. There are limited safety and tolerability data for administration of the capsule contents in
paediatric patients.
Table 1
Paediatric dose to be administered once daily*
Body Weight SUSTIVA
kg Dose (mg)
13 to < 15 200
15 to < 20 250
20 to < 25 300
25 to < 32.5 350
32.5 to < 40 400
≥ 40 600
*For information on the bioavailability of the capsule
contents mixed with food vehicles, see section 5.2.
3
 
4.3 Contraindications
Hypersensitivity to the active substance or to any of the excipients.
Efavirenz must not be used in patients with severe hepatic impairment (Child Pugh Class C) (see
section 5.2).
Efavirenz must not be administered concurrently with terfenadine, astemizole, cisapride, midazolam,
triazolam, pimozide, bepridil, or ergot alkaloids (for example, ergotamine, dihydroergotamine,
ergonovine, and methylergonovine) because competition for CYP3A4 by efavirenz could result in
inhibition of metabolism and create the potential for serious and/or life-threatening undesirable effects
[for example, cardiac arrhythmias, prolonged sedation or respiratory depression] (see section 4.5).
Herbal preparations containing St. John’s wort (Hypericum perforatum) must not be used while taking
efavirenz due to the risk of decreased plasma concentrations and reduced clinical effects of efavirenz
(see section 4.5).
4.4 Special warnings and precautions for use
Efavirenz must not be used as a single agent to treat HIV or added on as a sole agent to a failing
regimen. As with all other non-nucleoside reverse transcriptase inhibitors (NNRTIs), resistant virus
emerges rapidly when efavirenz is administered as monotherapy. The choice of new antiretroviral
agent(s) to be used in combination with efavirenz should take into consideration the potential for viral
cross-resistance (see section 5.1).
Co-administration of efavirenz with the fixed combination tablet containing efavirenz, emtricitabine,
and tenofovir disoproxil fumarate is not recommended.
When prescribing medicinal products concomitantly with SUSTIVA, physicians should refer to the
corresponding Summary of Product Characteristics.
Patients should be advised that current antiretroviral therapy, including efavirenz, has not been proven
to prevent the risk of transmission of HIV to others through sexual contact or blood contamination.
Appropriate precautions should continue to be employed.
If any antiretroviral medicinal product in a combination regimen is interrupted because of suspected
intolerance, serious consideration should be given to simultaneous discontinuation of all antiretroviral
medicinal products. The antiretroviral medicinal products should be restarted at the same time upon
resolution of the intolerance symptoms. Intermittent monotherapy and sequential reintroduction of
antiretroviral agents is not advisable because of the increased potential for selection of resistant virus.
Rash: mild-to-moderate rash has been reported in clinical studies with efavirenz and usually resolves
with continued therapy. Appropriate antihistamines and/or corticosteroids may improve the tolerability
and hasten the resolution of rash. Severe rash associated with blistering, moist desquamation or
ulceration has been reported in less than 1% of patients treated with efavirenz. The incidence of
erythema multiforme or Stevens-Johnson syndrome was approximately 0.1%. Efavirenz must be
discontinued in patients developing severe rash associated with blistering, desquamation, mucosal
involvement or fever. If therapy with efavirenz is discontinued, consideration should also be given to
interrupting therapy with other antiretroviral agents to avoid development of resistant virus (see
section 4.8).
Experience with efavirenz in patients who discontinued other antiretroviral agents of the NNRTI class
is limited (see section 4.8). Efavirenz is not recommended for patients who have had a life-threatening
cutaneous reaction (e.g., Stevens-Johnson syndrome) while taking another NNRTI.
Psychiatric symptoms: psychiatric adverse reactions have been reported in patients treated with
efavirenz. Patients with a prior history of psychiatric disorders appear to be at greater risk of these
4
serious psychiatric adverse reactions. In particular, severe depression was more common in those with
a history of depression. There have also been post-marketing reports of severe depression, death by
suicide, delusions and psychosis-like behaviour. Patients should be advised that if they experience
symptoms such as severe depression, psychosis or suicidal ideation, they should contact their doctor
immediately to assess the possibility that the symptoms may be related to the use of efavirenz, and if
so, to determine whether the risks of continued therapy outweigh the benefits (see section 4.8).
Nervous system symptoms: symptoms including, but not limited to, dizziness, insomnia, somnolence,
impaired concentration and abnormal dreaming are frequently reported undesirable effects in patients
receiving efavirenz 600 mg daily in clinical studies (see section 4.8). Nervous system symptoms
usually begin during the first one or two days of therapy and generally resolve after the first 2 - 4
weeks. Patients should be informed that if they do occur, these common symptoms are likely to
improve with continued therapy and are not predictive of subsequent onset of any of the less frequent
psychiatric symptoms.
Seizures: convulsions have been observed in patients receiving efavirenz, generally in the presence of
known medical history of seizures. Patients who are receiving concomitant anticonvulsant medicinal
products primarily metabolised by the liver, such as phenytoin, carbamazepine and phenobarbital, may
require periodic monitoring of plasma levels. In a drug interaction study, carbamazepine plasma
concentrations were decreased when carbamazepine was co-administered with efavirenz (see
section 4.5). Caution must be taken in any patient with a history of seizures.
Hepatic events: a few of the postmarketing reports of hepatic failure occurred in patients with no pre-
existing hepatic disease or other identifiable risk factors (see section 4.8). Liver enzyme monitoring
should be considered for patients without pre-existing hepatic dysfunction or other risk factors.
Effect of food: the administration of SUSTIVA with food may increase efavirenz exposure (see
section 5.2) and may lead to an increase in the frequency of adverse reactions (see section 4.8). It is
recommended that SUSTIVA be taken on an empty stomach, preferably at bedtime.
Immune Reactivation Syndrome: in HIV infected patients with severe immune deficiency at the time
of institution of combination antiretroviral therapy (CART), an inflammatory reaction to
asymptomatic or residual opportunistic pathogens may arise and cause serious clinical conditions, or
aggravation of symptoms. Typically, such reactions have been observed within the first few weeks or
months of initiation of CART. Relevant examples are cytomegalovirus retinitis, generalised and/or
focal mycobacterial infections, and pneumonia caused by Pneumocystis jiroveci (formerly known as
Pneumocystis carinii ). Any inflammatory symptoms should be evaluated and treatment instituted
when necessary.
Lipodystrophy and metabolic abnormalities: combination antiretroviral therapy has been associated
with the redistribution of body fat (lipodystrophy) in HIV patients. The long-term consequences of
these events are currently unknown. Knowledge about the mechanism is incomplete. A connection
between visceral lipomatosis and PIs and lipoatrophy and NRTIs has been hypothesised. A higher risk
of lipodystrophy has been associated with individual factors such as older age, and with drug related
factors such as longer duration of antiretroviral treatment and associated metabolic disturbances.
Clinical examination should include evaluation for physical signs of fat redistribution. Consideration
should be given to the measurement of fasting serum lipids and blood glucose. Lipid disorders should
be managed as clinically appropriate (see section 4.8).
Osteonecrosis: although the etiology is considered to be multifactorial (including corticosteroid use,
alcohol consumption, severe immunosuppression, higher body mass index), cases of osteonecrosis
have been reported particularly in patients with advanced HIV-disease and/or long-term exposure to
combination antiretroviral therapy (CART). Patients should be advised to seek medical advice if they
experience joint aches and pain, joint stiffness or difficulty in movement.
5
Special populations:
Liver disease : efavirenz is contraindicated in patients with severe hepatic impairment (see sections 4.3
and 5.2) and not recommended in patients with moderate hepatic impairment because of insufficient
data to determine whether dose adjustment is necessary. Because of the extensive cytochrome
P450-mediated metabolism of efavirenz and limited clinical experience in patients with chronic liver
disease, caution must be exercised in administering efavirenz to patients with mild hepatic impairment.
Patients should be monitored carefully for dose-related adverse reactions, especially nervous system
symptoms. Laboratory tests should be performed to evaluate their liver disease at periodic intervals
(see section 4.2).
The safety and efficacy of efavirenz has not been established in patients with significant underlying
liver disorders. Patients with chronic hepatitis B or C and treated with combination antiretroviral
therapy are at increased risk for severe and potentially fatal hepatic adverse reactions. Patients with
pre-existing liver dysfunction including chronic active hepatitis have an increased frequency of liver
function abnormalities during combination antiretroviral therapy and should be monitored according to
standard practice. If there is evidence of worsening liver disease or persistent elevations of serum
transaminases to greater than 5 times the upper limit of the normal range, the benefit of continued
therapy with efavirenz needs to be weighed against the potential risks of significant liver toxicity. In
such patients, interruption or discontinuation of treatment must be considered (see section 4.8).
In patients treated with other medicinal products associated with liver toxicity, monitoring of liver
enzymes is also recommended. In case of concomitant antiviral therapy for hepatitis B or C, please
refer also to the relevant product information for these medicinal products.
Renal insufficiency : the pharmacokinetics of efavirenz have not been studied in patients with renal
insufficiency; however, less than 1% of an efavirenz dose is excreted unchanged in the urine, so the
impact of renal impairment on efavirenz elimination should be minimal (see section 4.2). There is no
experience in patients with severe renal failure and close safety monitoring is recommended in this
population.
Elderly patients : insufficient numbers of elderly patients have been evaluated in clinical studies to
determine whether they respond differently than younger patients.
Paediatric population :
Efavirenz has not been evaluated in children below 3 years of age or who weigh less than 13 kg.
Therefore, efavirenz should not be given to children less than 3 years of age.
Rash was reported in 26 of 57 children (46%) treated with efavirenz during a 48-week period and was
severe in three patients. Prophylaxis with appropriate antihistamines prior to initiating therapy with
efavirenz in children may be considered.
Lactose: patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or
glucose-galactose malabsorption should not take this medicinal product. Individuals with these
conditions may take efavirenz oral solution, which is free from lactose.
4.5 Interaction with other medicinal products and other forms of interaction
Efavirenz is an inducer of CYP3A4 and an inhibitor of some CYP450 isoenzymes including CYP3A4
(see section 5.2). Other compounds that are substrates of CYP3A4 may have decreased plasma
concentrations when co-administered with efavirenz. Efavirenz exposure may also be altered when
given with medicinal products or food (for example, grapefruit juice) which affect CYP3A4 activity.
Contraindications of concomitant use
Efavirenz must not be administered concurrently with terfenadine, astemizole, cisapride, midazolam,
triazolam, pimozide, bepridil, or ergot alkaloids (for example, ergotamine, dihydroergotamine,
6
ergonovine, and methylergonovine), since inhibition of their metabolism may lead to serious,
life-threatening events (see section 4.3).
St. John’s wort (Hypericum perforatum): co-administration of efavirenz and St. John’s wort or herbal
preparations containing St. John’s wort is contraindicated. Plasma levels of efavirenz can be reduced
by concomitant use of St. John’s wort due to induction of drug metabolising enzymes and/or transport
proteins by St. John’s wort. If a patient is already taking St. John’s wort, stop St. John’s wort, check
viral levels and if possible efavirenz levels. Efavirenz levels may increase on stopping St. John’s wort
and the dose of efavirenz may need adjusting. The inducing effect of St. John’s wort may persist for at
least 2 weeks after cessation of treatment. (see section 4.3).
Other interactions
Interactions between efavirenz and protease inhibitors, antiretroviral agents other than protease
inhibitors and other non-antiretroviral medicinal products are listed in Table 2 below (increase is
indicated as “↑”, decrease as “↓”, no change as “↔”, and once every 8 or 12 hours as “q8h” or
“q12h”). If available, 90% or 95% confidence intervals are shown in parentheses. Studies were
conducted in healthy subjects unless otherwise noted.
Table 2: Interactions between efavirenz and other medicinal products
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
ANTI-INFECTIVES
Antiretrovirals
Protease inhibitors (PI)
Atazanavir/ ritonavir/Efavirenz
(400 mg once daily/100 mg once
daily/600 mg once daily, all
administered with food)
Atazanavir (pm):
AUC: ↔* (↓9 to ↑10)
C max : ↑17%* (↑8 to ↑27)
C min : ↓42%* (↓31 to ↓51)
Co-administration of efavirenz
with atazanavir/ritonavir is not
recommended. If the co-
administration of atazanavir
with an NNRTI is required, an
increase in the dose of both
atazanavir and ritonavir to
400 mg and 200 mg,
respectively, in combination
with efavirenz could be
considered with close clinical
monitoring.
Atazanavir/ritonavir/Efavirenz
(400 mg once daily/200 mg once
daily/600 mg once daily, all
administered with food)
Atazanavir (pm):
AUC: ↔*/** (↓10 to ↑26)
C max : ↔*/** (↓5 to ↑26)
C min : ↑ 12%*/** (↓16 to ↑49)
(CYP3A4 induction).
* When compared to atazanavir
300 mg/ritonavir 100 mg once daily in
the evening without efavirenz. This
decrease in atazanavir C min might
negatively impact the efficacy of
atazanavir.
** based on historical comparison
Darunavir/ritonavir/Efavirenz
(300 mg twice daily*/100 mg
twice daily/600 mg once daily)
Darunavir:
AUC: ↓ 13%
C min : ↓ 31%
(CYP3A4 induction)
Efavirenz:
AUC: ↑ 21%
C min : ↑ 17%
(CYP3A4 inhibition)
The clinical significance of the
changes has not been
established. Similar findings are
expected with the approved
darunavir/ritonavir 600/100 mg
twice daily dose. This
combination should be used
with caution. See ritonavir row
below.
*lower than recommended dose
Fosamprenavir/ritonavir/Efavirenz
(700 mg twice daily/100 mg twice
daily/600 mg once daily)
No clinically significant
pharmacokinetic interaction
No dose adjustment is necessary
for any of these medicinal
products. See also ritonavir row
below.
7
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
Fosamprenavir/Nelfinavir/
Efavirenz
Interaction not studied.
No dose adjustment is necessary
for any of these medicinal
products.
Fosamprenavir/Saquinavir/
Efavirenz
Interaction not studied.
Not recommended as the
exposure to both PIs is expected
to be significantly decreased.
Indinavir/Efavirenz
(800 mg q8h/200 mg once daily)
Indinavir:
AUC : ↓ 31% (↓ 8 to ↓ 47)
C min : ↓ 40%
A similar reduction in indinavir
exposures was observed when indinavir
1000 mg q8h was given with efavirenz
600 mg daily.
(CYP3A4 induction)
Efavirenz:
No clinically significant
pharmacokinetic interaction
While the clinical significance
of decreased indinavir
concentrations has not been
established, the magnitude of
the observed pharmacokinetic
interaction should be taken into
consideration when choosing a
regimen containing both
efavirenz and indinavir.
Indinavir/ritonavir/Efavirenz
(800 mg twice daily/100 mg twice
daily/600 mg once daily)
Indinavir:
AUC: ↓ 25% (↓ 16 to ↓ 32) b
C max : ↓ 17% (↓ 6 to ↓ 26) b
C min : ↓ 50% (↓ 40 to ↓ 59) b
Efavirenz:
No clinically significant
pharmacokinetic interaction
The geometric mean C min for indinavir
(0.33 mg/l) when given with ritonavir
and efavirenz was higher than the mean
historical C min (0.15 mg/l) when
indinavir was given alone at 800 mg
q8h. In HIV-1 infected patients (n = 6),
the pharmacokinetics of indinavir and
efavirenz were generally comparable to
these uninfected volunteer data.
No dose adjustment is necessary
for efavirenz when given with
indinavir or indinavir/ritonavir.
See also ritonavir row below.
Lopinavir/ritonavir soft capsules or
oral solution/Efavirenz
Substantial decrease in lopinavir
exposure.
With efavirenz, an increase of
the lopinavir/ritonavir soft
capsule or oral solution doses
by 33% should be considered
(4 capsules/~6.5 ml twice daily
instead of 3 capsules/5 ml twice
daily). Caution is warranted
since this dose adjustment
might be insufficient in some
patients. The dose of
lopinavir/ritonavir tablets
should be increased to
500/125 mg twice daily when
co-administered with efavirenz
600 mg once daily.
See also ritonavir row below.
Lopinavir/ritonavir tablets/
Efavirenz
(400/100 mg twice daily/600 mg
once daily)
(500/125 mg twice daily/600 mg
once daily)
Lopinavir concentrations: ↓ 30-40%
Lopinavir concentrations: similar to
lopinavir/ritonavir 400/100 mg twice
daily without efavirenz
Nelfinavir/Efavirenz
(750 mg q8h/600 mg once daily)
Nelfinavir:
AUC: ↑ 20% (↑ 8 to ↑ 34)
C max : ↑ 21% (↑ 10 to ↑ 33)
The combination was generally well
tolerated.
No dose adjustment is necessary
for either medicinal product.
8
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
Ritonavir/Efavirenz
(500 mg twice daily/600 mg once
daily)
Ritonavir:
Morning AUC: ↑ 18% (↑ 6 to ↑ 33)
Evening AUC: ↔
Morning C max : ↑ 24% (↑ 12 to ↑ 38)
Evening C max : ↔
Morning C min : ↑ 42% (↑ 9 to ↑ 86) b
Evening C min : ↑ 24% (↑ 3 to ↑ 50) b
Efavirenz:
AUC: ↑ 21% (↑ 10 to ↑ 34)
C max : ↑ 14% (↑ 4 to ↑ 26)
C min : ↑ 25% (↑ 7 to ↑ 46) b
(inhibition of CYP-mediated oxidative
metabolism)
When efavirenz was given with
ritonavir 500 mg or 600 mg twice
daily, the combination was not well
tolerated (for example, dizziness,
nausea, paraesthesia and elevated liver
enzymes occurred). Sufficient data on
the tolerability of efavirenz with
low-dose ritonavir (100 mg, once or
twice daily) are not available.
When using efavirenz with
low-dose ritonavir, the
possibility of an increase in the
incidence of
efavirenz-associated adverse
events should be considered,
due to possible
pharmacodynamic interaction.
Saquinavir/ritonavir/Efavirenz
Interaction not studied.
No data are available to make a
dose recommendation. See also
ritonavir row above. Use of
efavirenz in combination with
saquinavir as the sole protease
inhibitor is not recommended.
CCR5 antagonist
Maraviroc/Efavirenz
(100 mg twice daily/600 mg once
daily)
Maraviroc:
AUC 12 : ↓ 45% (↓ 38 to ↓ 51)
C max : ↓ 51% (↓ 37 to ↓ 62)
Efavirenz concentrations not measured,
no effect is expected.
Refer to the Summary of
Product Characteristics for the
medicinal product containing
maraviroc.
Integrase strand transfer inhibitor
Raltegravir/Efavirenz
(400 mg single dose/ -)
Raltegravir:
AUC: ↓ 36%
C 12 : ↓ 21%
C max : ↓ 36%
(UGT1A1 induction)
No dose adjustment is necessary
for raltegravir.
NRTIs and NNRTIs
NRTIs/Efavirenz
Specific interaction studies have not
been performed with efavirenz and
NRTIs other than lamivudine,
zidovudine, and tenofovir disoproxil
fumarate. Clinically significant
interactions are not expected since the
NRTIs are metabolised via a different
route than efavirenz and would be
unlikely to compete for the same
metabolic enzymes and elimination
pathways.
No dose adjustment is necessary
for either medicinal product.
NNRTIs/Efavirenz
Interaction not studied.
Since use of two NNRTIs
proved not beneficial in terms
of efficacy and safety,
co-administration of efavirenz
9
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
and another NNRTI is not
recommended.
Antibiotics
Azithromycin/Efavirenz
(600 mg single dose/400 mg once
daily)
No clinically significant
pharmacokinetic interaction.
No dose adjustment is necessary
for either medicinal product.
Clarithromycin/Efavirenz
(500 mg q12h/400 mg once daily)
Clarithromycin:
AUC: ↓ 39% (↓ 30 to ↓ 46)
C max : ↓ 26% (↓ 15 to ↓ 35)
Clarithromycin 14-hydroxymetabolite:
AUC: ↑ 34% (↑ 18 to ↑ 53)
C max : ↑ 49% (↑ 32 to ↑ 69)
Efavirenz:
AUC: ↔
C max : ↑ 11% (↑ 3 to ↑ 19)
(CYP3A4 induction)
Rash developed in 46% of uninfected
volunteers receiving efavirenz and
clarithromycin.
The clinical significance of
these changes in clarithromycin
plasma levels is not known.
Alternatives to clarithromycin
(e.g. azithromycin) may be
considered. No dose adjustment
is necessary for efavirenz.
Other macrolide antibiotics
(e.g.,erythromycin)/Efavirenz
Interaction not studied.
No data are available to make a
dose recommendation.
Antimycobacterials
Rifabutin/Efavirenz
(300 mg once daily/600 mg once
daily)
Rifabutin:
AUC: ↓ 38% (↓ 28 to ↓ 47)
C max : ↓ 32% (↓ 15 to ↓ 46)
C min : ↓ 45% (↓ 31 to ↓ 56)
Efavirenz:
AUC: ↔
C max :
C min : ↓ 12% (↓ 24 to ↑ 1)
(CYP3A4 induction)
The daily dose of rifabutin
should be increased by 50%
when administered with
efavirenz. Consider doubling
the rifabutin dose in regimens
where rifabutin is given 2 or
3 times a week in combination
with efavirenz.
Rifampicin/Efavirenz
(600 mg once daily/600 mg once
daily)
Efavirenz:
AUC: ↓ 26% (↓ 15 to ↓ 36)
C max : ↓ 20% (↓ 11 to ↓ 28)
C min : ↓ 32% (↓ 15 to ↓ 46)
(CYP3A4 and CYP2B6 induction)
When taken with rifampicin,
increasing efavirenz daily dose
to 800 mg may provide
exposure similar to a daily dose
of 600 mg when taken without
rifampicin. The clinical effect
of this dose adjustment has not
been adequately evaluated.
Individual tolerability and
virological response should be
considered when making the
dose adjustment (see section
5.2). No dose adjustment is
necessary for rifampicin.
10
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
Antifungals
Itraconazole/Efavirenz
(200 mg q12h/600 mg once daily)
Itraconazole:
AUC: ↓ 39% (↓ 21 to ↓ 53)
C max : ↓ 37% (↓ 20 to ↓ 51)
C min : ↓ 44% (↓ 27 to ↓ 58)
(decrease in itraconazole
concentrations: CYP3A4 induction)
Hydroxyitraconazole:
AUC: ↓ 37% (↓ 14 to ↓ 55)
C max : ↓ 35% (↓ 12 to ↓ 52)
C min : ↓ 43% (↓ 18 to ↓ 60)
Efavirenz:
No clinically significant
pharmacokinetic change.
Since no dose recommendation
for itraconazole can be made,
alternative antifungal treatment
should be considered.
Posaconazole/Efavirenz
--/400 mg once daily
Posaconazole:
AUC: ↓ 50%
C max : ↓ 45%
(UDP-G induction)
Concomitant use of
posaconazole and efavirenz
should be avoided unless the
benefit to the patient outweighs
the risk.
Voriconazole/Efavirenz
(200 mg twice daily/400 mg once
daily)
Voriconazole:
AUC: ↓ 77%
C max : ↓ 61%
Efavirenz:
AUC: ↑ 44%
C max : ↑ 38%
Voriconazole:
AUC: ↓ 7% (↓ 23 to ↑ 13) *
C max : ↑ 23% (↓ 1 to ↑ 53) *
Efavirenz:
AUC: ↑ 17% (↑ 6 to ↑ 29) **
C max : ↔**
*compared to 200 mg twice daily alone
** compared to 600 mg once daily
alone
(competitive inhibition of oxidative
metabolism)
When efavirenz is co-
administered with voriconazole,
the voriconazole maintenance
dose must be increased to
400 mg twice daily and the
efavirenz dose must be reduced
by 50%, i.e., to 300 mg once
daily. When treatment with
voriconazole is stopped, the
initial dose of efavirenz should
be restored.
Voriconazole/Efavirenz
(400 mg twice daily/300 mg once
daily)
Fluconazole/Efavirenz
(200 mg once daily/400 mg once
daily)
No clinically significant
pharmacokinetic interaction
No dose adjustment is necessary
for either medicinal product.
Ketoconazole and other imidazole
antifungals
Interaction not studied
No data are available to make a
dose recommendation.
11
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
ACID REDUCING AGENTS
Aluminium hydroxide-magnesium
hydroxide-simethicone
antacid/Efavirenz
(30 ml single dose/400 mg single
dose)
Famotidine/Efavirenz
(40 mg single dose/400 mg single
dose)
Neither aluminium/magnesium
hydroxide antacids nor famotidine
altered the absorption of efavirenz.
Co-administration of efavirenz
with medicinal products that
alter gastric pH would not be
expected to affect efavirenz
absorption.
ANTIANXIETY AGENTS
Lorazepam/Efavirenz
(2 mg single dose/600 mg once
daily)
Lorazepam:
AUC: ↑ 7% (↑ 1 to ↑ 14)
C max : ↑ 16% (↑ 2 to ↑ 32)
These changes are not considered
clinically significant.
No dose adjustment is necessary
for either medicinal product.
ANTICOAGULANTS
Warfarin/Efavirenz
Interaction not studied. Plasma
concentrations and effects of warfarin
are potentially increased or decreased
by efavirenz.
Dose adjustment of warfarin
may be required.
ANTICONVULSANTS
Carbamazepine/Efavirenz
(400 mg once daily/600 mg once
daily)
Carbamazepine:
AUC: ↓ 27% (↓ 20 to ↓ 33)
C max : ↓ 20% (↓ 15 to ↓ 24)
C min : ↓ 35% (↓ 24 to ↓ 44)
Efavirenz:
AUC: ↓ 36% (↓ 32 to ↓ 40)
C max : ↓ 21% (↓ 15 to ↓ 26)
C min : ↓ 47% (↓ 41 to ↓ 53)
(decrease in carbamazepine
concentrations: CYP3A4 induction;
decrease in efavirenz concentrations:
CYP3A4 and CYP2B6 induction)
The steady-state AUC, C max and C min
of the active carbamazepine epoxide
metabolite remained unchanged.
Co-administration of higher doses of
either efavirenz or carbamazepine has
not been studied.
No dose recommendation can
be made. An alternative
anticonvulsant should be
considered. Carbamazepine
plasma levels should be
monitored periodically.
Phenytoin, Phenobarbital, and
other anticonvulsants that are
substrates of CYP450 isoenzymes
Interaction not studied. There is a
potential for reduction or increase in
the plasma concentrations of
phenytoin, phenobarbital and other
anticonvulsants that are substrates of
CYP450 isoenzymes when co-
administered with efavirenz.
When efavirenz is co-
administered with an
anticonvulsant that is a substrate
of CYP450 isoenzymes,
periodic monitoring of
anticonvulsant levels should be
conducted.
Valproic acid/Efavirenz
(250 mg twice daily/600 mg once
daily)
No clinically significant effect on
efavirenz pharmacokinetics. Limited
data suggest there is no clinically
significant effect on valproic acid
pharmacokinetics.
No dose adjustment is necessary
for efavirenz. Patients should be
monitored for seizure control.
12
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
Vigabatrin/Efavirenz
Gabapentin/Efavirenz
Interaction not studied. Clinically
significant interactions are not expected
since vigabatrin and gabapentin are
exclusively eliminated unchanged in
the urine and are unlikely to compete
for the same metabolic enzymes and
elimination pathways as efavirenz.
No dose adjustment is necessary
for any of these medicinal
products.
ANTIDEPRESSANTS
Selective Serotonin Reuptake Inhibitors (SSRIs)
Sertraline/Efavirenz
(50 mg once daily/600 mg once
daily)
Sertraline:
AUC: ↓ 39% (↓ 27 to ↓ 50)
C max : ↓ 29% (↓ 15 to ↓ 40)
C min : ↓ 46% (↓ 31 to ↓ 58)
Efavirenz:
AUC: ↔
C max : ↑ 11% (↑ 6 to ↑ 16)
C min : ↔
(CYP3A4 induction)
Sertraline dose increases should
be guided by clinical response.
No dose adjustment is necessary
for efavirenz.
Paroxetine/Efavirenz
(20 mg once daily/600 mg once
daily)
No clinically significant
pharmacokinetic interaction
No dose adjustment is necessary
for either medicinal product.
Fluoxetine/Efavirenz
Interaction not studied. Since
fluoxetine shares a similar metabolic
profile with paroxetine, i.e. a strong
CYP2D6 inhibitory effect, a similar
lack of interaction would be expected
for fluoxetine.
No dose adjustment is necessary
for either medicinal product.
ANTIHISTAMINES
Cetirizine/Efavirenz
(10 mg single dose/600 mg once
daily)
Cetirizine:
AUC: ↔
C max : ↓ 24% (↓ 18 to ↓ 30)
These changes are not considered
clinically significant.
Efavirenz:
No clinically significant
pharmacokinetic interaction
No dose adjustment is necessary
for either medicinal product.
13
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
CARDIOVASCULAR AGENTS
Calcium Channel Blockers
Diltiazem/Efavirenz
(240 mg once daily/600 mg once
daily)
Diltiazem:
AUC: ↓ 69% (↓ 55 to ↓ 79)
C max : ↓ 60% (↓ 50 to ↓ 68)
C min : ↓ 63% (↓ 44 to ↓ 75)
Desacetyl diltiazem:
AUC: ↓ 75% (↓ 59 to ↓ 84)
C max : ↓ 64% (↓ 57 to ↓ 69)
C min : ↓ 62% (↓ 44 to ↓ 75)
N-monodesmethyl diltiazem:
AUC: ↓ 37% (↓ 17 to ↓ 52)
C max : ↓ 28% (↓ 7 to ↓ 44)
C min : ↓ 37% (↓ 17 to ↓ 52)
Efavirenz:
AUC: ↑ 11% (↑ 5 to ↑ 18)
C max : ↑ 16% (↑ 6 to ↑ 26)
C min : ↑ 13% (↑ 1 to ↑ 26)
(CYP3A4 induction)
The increase in efavirenz
pharmacokinetic parameters is not
considered clinically significant.
Dose adjustments of diltiazem
should be guided by clinical
response (refer to the Summary
of Product Characteristics for
diltiazem). No dose adjustment
is necessary for efavirenz.
Verapamil, Felodipine, Nifedipine
and Nicardipine
Interaction not studied. When efavirenz
is co-administered with a calcium
channel blocker that is a substrate of
the CYP3A4 enzyme, there is a
potential for reduction in the plasma
concentrations of the calcium channel
blocker.
Dose adjustments of calcium
channel blockers should be
guided by clinical response
(refer to the Summary of
Product Characteristics for the
calcium channel blocker).
LIPID LOWERING MEDICINAL PRODUCTS
HMG Co-A Reductase Inhibitors
Atorvastatin/Efavirenz
(10 mg once daily/600 mg once
daily)
Atorvastatin:
AUC: ↓ 43% (↓ 34 to ↓ 50)
C max : ↓ 12% (↓ 1 to ↓ 26)
2-hydroxy atorvastatin:
AUC: ↓ 35% (↓ 13 to ↓ 40)
C max : ↓ 13% (↓ 0 to ↓ 23)
4-hydroxy atorvastatin:
AUC: ↓ 4% (↓ 0 to ↓ 31)
C max : ↓ 47% (↓ 9 to ↓ 51)
Total active HMG Co-A reductase
inhibitors:
AUC: ↓ 34% (↓ 21 to ↓ 41)
C max : ↓ 20% (↓ 2 to ↓ 26)
Cholesterol levels should be
periodically monitored. Dose
adjustment of atorvastatin may
be required (refer to the
Summary of Product
Characteristics for atorvastatin).
No dose adjustment is necessary
for efavirenz.
Pravastatin/Efavirenz
(40 mg once daily/600 mg once
daily)
Pravastatin:
AUC: ↓ 40% (↓ 26 to ↓ 57)
C max : ↓ 18% (↓ 59 to ↑ 12)
Cholesterol levels should be
periodically monitored. Dose
adjustment of pravastatin may
be required (refer to the
Summary of Product
Characteristics for pravastatin).
No dose adjustment is necessary
for efavirenz.
14
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
Simvastatin/Efavirenz
(40 mg once daily/600 mg once
daily)
Simvastatin:
AUC: ↓ 69% (↓ 62 to ↓ 73)
C max : ↓ 76% (↓ 63 to ↓ 79)
Simvastatin acid:
AUC: ↓ 58% (↓ 39 to ↓ 68)
C max : ↓ 51% (↓ 32 to ↓ 58)
Total active HMG Co-A reductase
inhibitors:
AUC: ↓ 60% (↓ 52 to ↓ 68)
C max : ↓ 62% (↓ 55 to ↓ 78)
(CYP3A4 induction)
Co-administration of efavirenz with
atorvastatin, pravastatin, or
simvastatin did not affect efavirenz
AUC or C max values.
Cholesterol levels should be
periodically monitored. Dose
adjustment of simvastatin may
be required (refer to the
Summary of Product
Characteristics for simvastatin).
No dose adjustment is necessary
for efavirenz.
Rosuvastatin/Efavirenz
Interaction not studied. Rosuvastatin is
largely excreted unchanged via the
faeces, therefore interaction with
efavirenz is not expected.
No dose adjustment is necessary
for either medicinal product.
HORMONAL CONTRACEPTIVES
Oral:
Ethinyloestradiol + Norgestimate/
Efavirenz
(0.035 mg + 0.25 mg once
daily/600 mg once daily)
Ethinyloestradiol:
AUC: ↔
C max : ↔
C min : ↓ 8% (↑ 14 to ↓ 25)
Norelgestromin (active metabolite):
AUC: ↓ 64% (↓ 62 to ↓ 67)
C max : ↓ 46% (↓ 39 to ↓ 52)
C min : ↓ 82% (↓ 79 to ↓ 85)
Levonorgestrel (active metabolite):
AUC: ↓ 83% (↓ 79 to ↓ 87)
C max : ↓ 80% (↓ 77 to ↓ 83)
C min : ↓ 86% (↓ 80 to ↓ 90)
(induction of metabolism)
Efavirenz: no clinically significant
interaction.
The clinical significance of these
effects is not known.
A reliable method of barrier
contraception must be used in
addition to hormonal
contraceptives (see section 4.6).
Injection: Depomedroxyprogesterone
acetate (DMPA)/Efavirenz
(150 mg IM single dose DMPA)
In a 3-month drug interaction study, no
significant differences in MPA
pharmacokinetic parameters were found
between subjects receiving efavirenz-
containing antiretroviral therapy and
subjects receiving no antiretroviral
therapy. Similar results were found by
other investigators, although the MPA
plasma levels were more variable in the
second study. In both studies, plasma
progesterone levels for subjects receiving
efavirenz and DMPA remained low
consistent with suppression of ovulation.
Because of the limited
information available, a reliable
method of barrier contraception
must be used in addition to
hormonal contraceptives (see
section 4.6).
Implant: Etonogestrel/Efavirenz
Interaction not studied. Decreased
exposure of etonogestrel may be
expected (CYP3A4 induction). There
have been occasional postmarketing
reports of contraceptive failure with
etonogestrel in efavirenz-exposed
patients.
A reliable method of barrier
contraception must be used in
addition to hormonal
contraceptives (see section 4.6).
15
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
IMMUNOSUPPRESSANTS
Immunosuppressants metabolized
by CYP3A4 (eg, cyclosporine,
tacrolimus, sirolimus)/Efavirenz
Interaction not studied. Decreased
exposure of the immunosuppressant
may be expected (CYP3A4 induction).
These immunosuppressants are not
anticipated to affect exposure of
efavirenz.
Dose adjustments of the
immunosuppressant may be
required. Close monitoring of
immunosuppressant
concentrations for at least 2
weeks (until stable
concentrations are reached) is
recommended when starting or
stopping treatment with
efavirenz.
OPIOIDS
Methadone/Efavirenz
(stable maintenance, 35-100 mg
once daily/600 mg once daily)
Methadone:
AUC: ↓ 52% (↓ 33 to ↓ 66)
C max : ↓ 45% (↓ 25 to ↓ 59)
(CYP3A4 induction)
In a study of HIV infected intravenous
drug users, co-administration of
efavirenz with methadone resulted in
decreased plasma levels of methadone
and signs of opiate withdrawal. The
methadone dose was increased by a
mean of 22% to alleviate withdrawal
symptoms.
Patients should be monitored
for signs of withdrawal and
their methadone dose increased
as required to alleviate
withdrawal symptoms.
Buprenorphine/naloxone/Efavirenz Buprenorphine:
AUC: ↓ 50%
Norbuprenorphine:
AUC: ↓ 71%
Efavirenz:
No clinically significant
pharmacokinetic interaction
Despite the decrease in
buprenorphine exposure, no
patients exhibited withdrawal
symptoms. Dose adjustment of
buprenorphine or efavirenz may
not be necessary when co-
administered.
a 90% confidence intervals unless otherwise noted.
b 95% confidence intervals.
Paediatric population
Interaction studies have only been performed in adults.
4.6 Fertility, pregnancy and lactation
Efavirenz should not be used during pregnancy unless there are no other appropriate treatment options.
Women of childbearing potential: pregnancy should be avoided in women treated with efavirenz.
Barrier contraception should always be used in combination with other methods of contraception (for
example, oral or other hormonal contraceptives). Because of the long half-life of efavirenz, use of
adequate contraceptive measures for 12 weeks after discontinuation of efavirenz is recommended.
Women of childbearing potential should undergo pregnancy testing before initiation of efavirenz.
Pregnancy: there are limited amount of data from the use of efavirenz in pregnant women. In
postmarketing experience through an antiretroviral pregnancy registry, outcomes for more than
400 pregnancies with first-trimester exposure to efavirenz as part of a combination antiretroviral
regimen have been prospectively reported with no specific malformation pattern observed. A small
number of cases of neural tube defects, including meningomyelocele, have been reported via the
registry. Most neural tube defects were isolated retrospectively reported cases, and causality cannot be
16
 
ruled out but has not been established. Studies in animals have shown reproductive toxicity including
marked teratogenic effects (see section 5.3).
Breastfeeding: studies in rats have demonstrated that efavirenz is excreted in milk reaching
concentrations much higher than those in maternal plasma. It is not known whether efavirenz is
excreted in human milk. Since animal data suggest that the substance may be passed into breast milk,
it is recommended that mothers taking efavirenz do not breast feed their infants. It is recommended
that HIV infected women do not breast feed their infants under any circumstances in order to avoid
transmission of HIV.
Fertility: the effect of efavirenz on male and female fertility in rats has only been evaluated at doses
that achieved systemic drug exposures equivalent to or below those achieved in humans given
recommended doses of efavirenz. In these studies, efavirenz did not impair mating or fertility of male
or female rats (doses up to 100 mg/kg/bid), and did not affect sperm or offspring of treated male rats
(doses up to 200 mg/bid). The reproductive performance of offspring born to female rats given
efavirenz was not affected.
4.7 Effects on ability to drive and use machines
Efavirenz may cause dizziness, impaired concentration, and/or somnolence. Patients should be
instructed that if they experience these symptoms they should avoid potentially hazardous tasks such
as driving or operating machinery.
4.8 Undesirable effects
a. Summary of the safety profile
Efavirenz has been studied in over 9,000 patients. In a subset of 1,008 adult patients who received
600 mg efavirenz daily in combination with PIs and/or NRTIs in controlled clinical studies, the most
frequently reported adverse reactions of at least moderate severity reported in at least 5% of patients
were rash (11.6%), dizziness (8.5%), nausea (8.0%), headache (5.7%) and fatigue (5.5%). The most
notable adverse reactions associated with efavirenz are rash and nervous system symptoms. Nervous
system symptoms usually begin soon after therapy onset and generally resolve after the first 2 - 4
weeks. Severe skin reactions such as Stevens-Johnson syndrome and erythema multiforme; psychiatric
adverse reactions including severe depression, death by suicide, and psychosis like behaviour; and
seizures have been reported in patients treated with efavirenz. The administration of SUSTIVA with
food may increase efavirenz exposure and may lead to an increase in the frequency of adverse
reactions (see section 4.4).
The long-term safety profile of efavirenz-containing regimens was evaluated in a controlled trial (006)
in which patients received efavirenz + zidovudine + lamivudine (n = 412, median duration
180 weeks), efavirenz + indinavir (n = 415, median duration 102 weeks), or indinavir + zidovudine +
lamivudine (n = 401, median duration 76 weeks). Long-term use of efavirenz in this study was not
associated with any new safety concerns.
b. Tabulated list of adverse reactions
Adverse reactions of moderate or greater severity with at least possible relationship to treatment
regimen (based on investigator attribution) reported in clinical trials of efavirenz at the recommended
dose in combination therapy (n = 1,008) are listed below. Also listed in italics are adverse reactions
observed post-marketing in association with efavirenz-containing antiretroviral treatment regimens.
Frequency is defined using the following convention: very common (≥ 1/10); common (≥ 1/100 to
< 1/10); uncommon (≥ 1/1,000 to < 1/100); rare (≥ 1/10,000 to < 1/1,000); or very rare (< 1/10,000).
Immune system disorders
uncommon
hypersensitivity
17
 
Psychiatric disorders
common
abnormal dreams, anxiety, depression,
insomnia*
uncommon
affect lability, aggression, confusional state,
euphoric mood, hallucination, mania,
paranoia, psychosis , suicide attempt, suicide
ideation*
rare
delusion , neurosis , completed suicide ‡, *
Nervous system disorders
common
cerebellar coordination and balance
disturbances , disturbance in attention
(3.6%), dizziness (8.5%), headache (5.7%),
somnolence (2.0%)*
uncommon
agitation, amnesia, ataxia, coordination
abnormal, convulsions, thinking abnormal,*
tremo r
Eye disorders
uncommon
vision blurred
Ear and labyrinth disorders
uncommon
tinnitus , vertigo
Vascular disorders
uncommon
flushing
Gastrointestinal disorders
common
abdominal pain, diarrhoea, nausea, vomiting
uncommon
pancreatitis
Hepatobiliary disorders
uncommon
hepatitis acute
rare
hepatic failure ‡, *
Skin and subcutaneous tissue disorders
very common
rash (11.6%)*
common
pruritus
uncommon
erythema multiforme, Stevens-Johnson
syndrome*
rare
photoallergic dermatitis
Reproductive system and breast disorders
uncommon
gynaecomastia
General disorders and administration site conditions
common
fatigue
* See section c. Description of selected adverse reactions for more details.
18
 
These adverse reactions were identified through post-marketing surveillance; however, the
frequencies were determined using data from 16 clinical trials (n=3,969).
These adverse reactions were identified through post-marketing surveillance but not reported as drug-
related events for efavirenz-treated patients in 16 clinical trials. The frequency category of "rare" was
defined per A Guideline on Summary of Product Characteristics (SmPC) (rev. 2, Sept 2009) on the
basis of an estimated upper bound of the 95% confidence interval for 0 events given the number of
patients treated with efavirenz in these clinical trials (n=3,969).
c. Description of selected adverse reactions
Rash: in clinical studies, 26% of patients treated with 600 mg of efavirenz experienced skin rash
compared with 17% of patients treated in control groups. Skin rash was considered treatment related in
18% of patients treated with efavirenz. Severe rash occurred in less than 1% of patients treated with
efavirenz, and 1.7% discontinued therapy because of rash. The incidence of erythema multiforme or
Stevens-Johnson syndrome was approximately 0.1%.
Rashes are usually mild-to-moderate maculopapular skin eruptions that occur within the first two
weeks of initiating therapy with efavirenz. In most patients rash resolves with continuing therapy with
efavirenz within one month. Efavirenz can be reinitiated in patients interrupting therapy because of
rash. Use of appropriate antihistamines and/or corticosteroids is recommended when efavirenz is
restarted.
Experience with efavirenz in patients who discontinued other antiretroviral agents of the NNRTI class
is limited. Reported rates of recurrent rash following a switch from nevirapine to efavirenz therapy,
primarily based on retrospective cohort data from published literature, range from 13 to 18%,
comparable to the rate observed in patients treated with efavirenz in clinical studies. (See section 4.4.)
Psychiatric symptoms: serious psychiatric adverse reactions have been reported in patients treated with
efavirenz. In controlled trials, the frequency of specific serious psychiatric events were:
Efavirenz regimen
(n=1,008)
Control regimen
(n=635)
- severe depression
1.6%
0.6%
- suicidal ideation
0.6%
0.3%
- non-fatal suicide attempts
0.4%
0%
- aggressive behaviour
0.4%
0.3%
- paranoid reactions
0.4%
0.3%
- manic reactions
0.1%
0%
Patients with a history of psychiatric disorders appear to be at greater risk of these serious psychiatric
adverse reactions with frequencies ranging from 0.3% for manic reactions to 2.0% for both severe
depression and suicidal ideation. There have also been post-marketing reports of death by suicide,
delusions and psychosis-like behaviour.
Nervous system symptoms: in clinical controlled trials, frequently reported adverse reactions included,
but were not limited to dizziness, insomnia, somnolence, impaired concentration and abnormal
dreaming. Nervous system symptoms of moderate-to-severe intensity were experienced by 19%
(severe 2%) of patients compared to 9% (severe 1%) of patients receiving control regimens. In clinical
studies 2% of patients treated with efavirenz discontinued therapy due to such symptoms.
Nervous system symptoms usually begin during the first one or two days of therapy and generally
resolve after the first 2 - 4 weeks. In a study of uninfected volunteers, a representative nervous system
symptom had a median time to onset of 1 hour post-dose and a median duration of 3 hours. Nervous
system symptoms may occur more frequently when efavirenz is taken concomitantly with meals
possibly due to increased efavirenz plasma levels (see section 5.2). Dosing at bedtime seems to
improve the tolerability of these symptoms and can be recommended during the first weeks of therapy
19
and in patients who continue to experience these symptoms (see section 4.2). Dose reduction or
splitting the daily dose has not been shown to provide benefit.
Analysis of long-term data showed that, beyond 24 weeks of therapy, the incidences of new-onset
nervous system symptoms among efavirenz-treated patients were generally similar to those in the
control arm.
Hepatic failure: A few of the postmarketing reports of hepatic failure, including cases in patients with
no pre-existing hepatic disease or other identifiable risk factors, were characterized by a fulminant
course, progressing in some cases to transplantation or death.
Immune Reactivation Syndrome: in HIV infected patients with severe immune deficiency at the time
of initiation of combination antiretroviral therapy (CART), an inflammatory reaction to asymptomatic
or residual opportunistic infections may arise (see section 4.4).
Lipodystrophy and metabolic abnormalities: combination antiretroviral therapy has been associated
with redistribution of body fat (lipodystrophy) in HIV patients including the loss of peripheral and
facial subcutaneous fat, increased intra-abdominal and visceral fat, breast hypertrophy and
dorsocervical fat accumulation (buffalo hump).
Combination antiretroviral therapy has been associated with metabolic abnormalities such as
hypertriglyceridaemia, hypercholesterolaemia, insulin resistance, hyperglycaemia and
hyperlactataemia (see section 4.4).
Osteonecrosis: cases of osteonecrosis have been reported, particularly in patients with generally
acknowledged risk factors, advanced HIV disease or long-term exposure to combination antiretroviral
therapy (CART). The frequency of this is unknown (see section 4.4).
Laboratory test abnormalities:
Liver enzymes : elevations of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) to
greater than five times the upper limit of the normal range (ULN) were seen in 3% of 1,008 patients
treated with 600 mg of efavirenz (5-8% after long-term treatment in study 006). Similar elevations
were seen in patients treated with control regimens (5% after long-term treatment). Elevations of
gamma-glutamyltransferase (GGT) to greater than five times ULN were observed in 4% of all patients
treated with 600 mg of efavirenz and 1.5-2% of patients treated with control regimens (7% of
efavirenz-treated patients and 3% of control-treated patients after long-term treatment). Isolated
elevations of GGT in patients receiving efavirenz may reflect enzyme induction. In the long-term
study (006), 1% of patients in each treatment arm discontinued because of liver or biliary system
disorders.
Amylase : in the clinical trial subset of 1,008 patients, asymptomatic increases in serum amylase levels
greater than 1.5 times the upper limit of normal were seen in 10% of patients treated with efavirenz
and 6% of patients treated with control regimens. The clinical significance of asymptomatic increases
in serum amylase is unknown.
Lipids : increases in total cholesterol of 10 - 20% have been observed in some uninfected volunteers
receiving efavirenz. In clinical trials of various efavirenz-containing regimens in treatment naive
patients, total cholesterol, HDL-cholesterol, and triglycerides increased over 48 weeks of treatment
(21 - 31%, 23 - 34%, and 23 - 49%, respectively). The proportion of patients with a total
cholesterol/HDL-cholesterol ratio greater than 5 was unchanged. The magnitude of changes in lipid
levels may be influenced by factors such as duration of therapy and other components of the
antiretroviral regimen.
Cannabinoid test interaction : efavirenz does not bind to cannabinoid receptors. False positive urine
cannabinoid test results have been reported in uninfected volunteers who received efavirenz. False
positive test results have only been observed with the CEDIA DAU Multi-Level THC assay, which is
20
used for screening, and have not been observed with other cannabinoid assays tested including tests
used for confirmation of positive results.
d. Paediatric population
Undesirable effects in children were generally similar to those of adult patients. Rash was reported
more frequently in children (in a clinical study including 57 children who received efavirenz during a
48-week period, rash was reported in 46%) and was more often of higher grade than in adults (severe
rash was reported in 5.3% of children). Prophylaxis with appropriate antihistamines prior to initiating
therapy with efavirenz in children may be considered. Although nervous system symptoms are
difficult for young children to report, they appear to be less frequent in children and were generally
mild. In the study of 57 children, 3.5% of patients experienced nervous system symptoms of moderate
intensity, predominantly dizziness. No child had severe symptoms or had to discontinue because of
nervous system symptoms.
e. Other special populations
Liver enzymes in hepatitis B or C co-infected patients : in the long-term data set from study 006,
137 patients treated with efavirenz-containing regimens (median duration of therapy, 68 weeks) and
84 treated with a control regimen (median duration, 56 weeks) were seropositive at screening for
hepatitis B (surface antigen positive) and/or C (hepatitis C antibody positive). Among these
co-infected patients in study 006, elevations in AST to greater than five times ULN developed in 13%
of efavirenz-treated patients and in 7% of controls, and elevations in ALT to greater than five times
ULN developed in 20% and 7%, respectively. Among co-infected patients, 3% of those treated with
efavirenz and 2% in the control arm discontinued because of liverdisorders (see section 4.4).
4.9 Overdose
Some patients accidentally taking 600 mg twice daily have reported increased nervous system
symptoms. One patient experienced involuntary muscle contractions.
Treatment of overdose with efavirenz should consist of general supportive measures, including
monitoring of vital signs and observation of the patient’s clinical status. Administration of activated
charcoal may be used to aid removal of unabsorbed efavirenz. There is no specific antidote for
overdose with efavirenz. Since efavirenz is highly protein bound, dialysis is unlikely to remove
significant quantities of it from blood.
5.
PHARMACOLOGICAL PROPERTIES
5.1 Pharmacodynamic properties
Pharmacotherapeutic group: Non-nucleoside reverse transcriptase inhibitors.
ATC code: J05AG03
Mechanism of action: efavirenz is a NNRTI of HIV-1. Efavirenz is a non-competitive inhibitor of
HIV-1 reverse transcriptase (RT) and does not significantly inhibit HIV-2 RT or cellular DNA
polymerases (α, β, γ or δ).
Antiviral activity: the free concentration of efavirenz required for 90 to 95% inhibition of wild type or
zidovudine-resistant laboratory and clinical isolates in vitro ranged from 0.46 to 6.8 nM in
lymphoblastoid cell lines, peripheral blood mononuclear cells (PBMCs) and macrophage/monocyte
cultures.
Resistance: the potency of efavirenz in cell culture against viral variants with amino acid substitutions
at positions 48, 108, 179, 181 or 236 in RT or variants with amino acid substitutions in the protease
was similar to that observed against wild type viral strains. The single substitutions which led to the
21
highest resistance to efavirenz in cell culture correspond to a leucine-to-isoleucine change at position
100 (L100I, 17 to 22-fold resistance) and a lysine-to-asparagine at position 103 (K103N, 18 to 33-fold
resistance). Greater than 100-fold loss of susceptibility was observed against HIV variants expressing
K103N in addition to other amino acid substitutions in RT.
K103N was the most frequently observed RT substitution in viral isolates from patients who
experienced a significant rebound in viral load during clinical studies of efavirenz in combination with
indinavir or zidovudine + lamivudine. This mutation was observed in 90% of patients receiving
efavirenz with virological failure. Substitutions at RT positions 98, 100, 101, 108, 138, 188, 190 or
225 were also observed, but at lower frequencies, and often only in combination with K103N. The
pattern of amino acid substitutions in RT associated with resistance to efavirenz was independent of
the other antiviral medications used in combination with efavirenz.
Cross resistance: cross resistance profiles for efavirenz, nevirapine and delavirdine in cell culture
demonstrated that the K103N substitution confers loss of susceptibility to all three NNRTIs. Two of
three delavirdine-resistant clinical isolates examined were cross-resistant to efavirenz and contained
the K103N substitution. A third isolate which carried a substitution at position 236 of RT was not
cross-resistant to efavirenz.
Viral isolates recovered from PBMCs of patients enrolled in efavirenz clinical studies who showed
evidence of treatment failure (viral load rebound) were assessed for susceptibility to NNRTIs. Thirteen
isolates previously characterised as efavirenz-resistant were also resistant to nevirapine and
delavirdine. Five of these NNRTI-resistant isolates were found to have K103N or a valine-to-
isoleucine substitution at position 108 (V108I) in RT. Three of the efavirenz treatment failure isolates
tested remained sensitive to efavirenz in cell culture and were also sensitive to nevirapine and
delavirdine.
The potential for cross resistance between efavirenz and PIs is low because of the different enzyme
targets involved. The potential for cross-resistance between efavirenz and NRTIs is low because of the
different binding sites on the target and mechanism of action.
Clinical efficacy:
Efavirenz has not been studied in controlled studies in patients with advanced HIV disease, namely
with CD4 counts < 50 cells/mm 3 , or in PI or NNRTI experienced patients. Clinical experience in
controlled studies with combinations including didanosine or zalcitabine is limited.
Two controlled studies (006 and ACTG 364) of approximately one year duration with efavirenz in
combination with NRTIs and/or PIs, have demonstrated reduction of viral load below the limit of
quantification of the assay and increased CD4 lymphocytes in antiretroviral therapy-naïve and
NRTI-experienced HIV-infected patients. Study 020 showed similar activity in NRTI-experienced
patients over 24 weeks. In these studies the dose of efavirenz was 600 mg once daily; the dose of
indinavir was 1,000 mg every 8 hours when used with efavirenz and 800 mg every 8 hours when used
without efavirenz. The dose of nelfinavir was 750 mg given three times a day. The standard doses of
NRTIs given every 12 hours were used in each of these studies.
Study 006, a randomized, open-label trial, compared efavirenz + zidovudine + lamivudine or
efavirenz + indinavir with indinavir + zidovudine + lamivudine in 1,266 patients who were required to
be efavirenz-, lamivudine-, NNRTI-, and PI-naive at study entry. The mean baseline CD4 cell count
was 341 cells/mm 3 and the mean baseline HIV-RNA level was 60,250 copies/ml. Efficacy results for
study 006 on a subset of 614 patients who had been enrolled for at least 48 weeks are found in Table 3.
In the analysis of responder rates (the non-completer equals failure analysis [NC = F]), patients who
terminated the study early for any reason, or who had a missing HIV-RNA measurement that was
either preceded or followed by a measurement above the limit of assay quantification were considered
to have HIV-RNA above 50 or above 400 copies/ml at the missing time points.
22
Table 3: Efficacy results for study 006
Responder rates (NC = F a )
Plasma HIV-RNA
Mean change
from
baseline-CD4
cell count
< 400 copies/ml
(95% C.I. b )
< 50 copies/ml
(95% C.I. b )
cells/mm 3
(S.E.M. c )
Treatment
Regimen d
n
48 weeks
48 weeks
48 weeks
EFV +
ZDV + 3TC
202
67%
(60%, 73%)
62%
(55%, 69%)
187
(11.8)
EFV + IDV 206
54%
(47%, 61%)
48%
(41%, 55%)
177
(11.3)
IDV +
ZDV + 3TC
206
45%
(38%, 52%)
40%
(34%, 47%)
153
(12.3)
a NC = F, noncompleter = failure.
b C.I., confidence interval.
c S.E.M., standard error of the mean.
d
EFV, efavirenz; ZDV, zidovudine; 3TC, lamivudine; IDV, indinavir.
Long-term results at 168 weeks of study 006 (160 patients completed study on treatment with
EFV+IDV, 196 patients with EFV+ZDV+3TC and 127 patients with IDV+ZDV+3TC, respectively),
suggest durability of response in terms of proportions of patients with HIV RNA < 400 copies/ml,
HIV RNA < 50 copies/ml and in terms of mean change from baseline CD4 cell count.
Efficacy results for studies ACTG 364 and 020 are found in Table 4. Study ACTG 364 enrolled
196 patients who had been treated with NRTIs but not with PIs or NNRTIs. Study 020 enrolled
327 patients who had been treated with NRTIs but not with PIs or NNRTIs. Physicians were allowed
to change their patient’s NRTI regimen upon entry into the study. Responder rates were highest in
patients who switched NRTIs.
Table 4: Efficacy results for studies ACTG 364 and 020
Responder rates (NC = F a )
Plasma HIV-RNA
Mean change from
baseline-CD4 cell
count
Study Number/
Treatment Regimens b
n
%
(95% C.I. c )
% (95% C.I.) cells/mm 3 (S.E.M. d )
Study ACTG 364
48 weeks
< 500 copies/ml
< 50 copies/ml
EFV + NFV + NRTIs
65 70
(59, 82)
---
---
107
(17.9)
EFV + NRTIs
65 58
(46, 70)
---
---
114
(21.0)
NFV + NRTIs
66 30
(19, 42)
---
---
94
(13.6)
Study 020
24 weeks
< 400 copies/ml
< 50 copies/ml
EFV + IDV + NRTIs
157 60
(52, 68)
49
(41, 58)
104
(9.1)
IDV + NRTIs
170 51
(43, 59)
38
(30, 45)
77
(9.9)
a NC = F, noncompleter = failure.
b EFV, efavirenz; ZDV, zidovudine; 3TC, lamivudine; IDV, indinavir; NRTI, nucleoside reverse transcriptase inhibitor;
NFV, nelfinavir.
c C.I., confidence interval for proportion of patients in response.
d S.E.M., standard error of the mean.
---, not performed.
23
 
Paediatric population: ACTG 382 is an ongoing uncontrolled study of 57 NRTI-experienced
paediatric patients (3 - 16 years) which characterises the pharmacokinetics, antiviral activity and safety
of efavirenz in combination with nelfinavir (20 - 30 mg/kg given three times a day) and one or more
NRTIs. The starting dose of efavirenz was the equivalent of a 600 mg dose (adjusted from calculated
body size based on weight). The response rate, based on the NC = F analysis of the percentage of
patients with plasma HIV-RNA < 400 copies/ml at 48 weeks was 60% (95%, C.I. 47, 72), and 53%
(C.I. 40, 66) based on percentage of patients with plasma HIV-RNA < 50 copies/ml. The mean CD4
cell counts were increased by 63 ± 34.5 cells/mm 3 from baseline. The durability of the response was
similar to that seen in adult patients.
5.2 Pharmacokinetic properties
Absorption: peak efavirenz plasma concentrations of 1.6 - 9.1 μM were attained by 5 hours following
single oral doses of 100 mg to 1,600 mg administered to uninfected volunteers. Dose related increases
in C max and AUC were seen for doses up to 1,600 mg; the increases were less than proportional
suggesting diminished absorption at higher doses. Time to peak plasma concentrations (3 - 5 hours)
did not change following multiple dosing and steady-state plasma concentrations were reached in
6 - 7 days.
In HIV infected patients at steady state, mean C max , mean C min , and mean AUC were linear with
200 mg, 400 mg, and 600 mg daily doses. In 35 patients receiving efavirenz 600 mg once daily, steady
state C max was 12.9 ± 3.7 μM (29%) mean ± S.D. (% C.V.), steady state C min was
5.6 ± 3.2 μM (57%), and AUC was 184 ± 73 μM·h (40%).
Effect of food: the bioavailability of a single 600 mg dose of efavirenz hard capsules in uninfected
volunteers was increased 22% and 17%, respectively, when given with a meal of high fat or normal
composition, relative to the bioavailability of a 600 mg dose given under fasted conditions (see
section 4.4).
Bioavailability of hard capsule contents mixed with food vehicles: in healthy adult subjects, the
efavirenz AUC when administered as the contents of three 200 mg hard capsules mixed with
2 teaspoons of certain food vehicles (applesauce, grape jelly, yogurt or infant formula) met
bioequivalency criteria for the AUC of the intact capsule formulation administered under fasted
conditions.
Distribution: efavirenz is highly bound (approximately 99.5 - 99.75%) to human plasma proteins,
predominantly albumin. In HIV-1 infected patients (n = 9) who received efavirenz 200 to 600 mg once
daily for at least one month, cerebrospinal fluid concentrations ranged from 0.26 to 1.19%
(mean 0.69%) of the corresponding plasma concentration. This proportion is approximately 3-fold
higher than the non-protein-bound (free) fraction of efavirenz in plasma.
Biotransformation: studies in humans and in vitro studies using human liver microsomes have
demonstrated that efavirenz is principally metabolised by the cytochrome P450 system to
hydroxylated metabolites with subsequent glucuronidation of these hydroxylated metabolites. These
metabolites are essentially inactive against HIV-1. The in vitro studies suggest that CYP3A4 and
CYP2B6 are the major isozymes responsible for efavirenz metabolism and that it inhibited
P450 isozymes 2C9, 2C19, and 3A4. In in vitro studies efavirenz did not inhibit CYP2E1 and
inhibited CYP2D6 and CYP1A2 only at concentrations well above those achieved clinically.
Efavirenz plasma exposure may be increased in patients with the homozygous G516T genetic variant
of the CYP2B6 isoenzyme. The clinical implications of such an association are unknown; however,
the potential for an increased frequency and severity of efavirenz-associated adverse events cannot be
excluded.
Efavirenz has been shown to induce P450 enzymes, resulting in the induction of its own metabolism.
In uninfected volunteers, multiple doses of 200 - 400 mg per day for 10 days resulted in a lower than
24
predicted extent of accumulation (22 - 42% lower) and a shorter terminal half-life compared with
single dose administration (see below).
Elimination: efavirenz has a relatively long terminal half-life of at least 52 hours after single doses and
40 - 55 hours after multiple doses. Approximately 14 - 34% of a radiolabelled dose of efavirenz was
recovered in the urine and less than 1% of the dose was excreted in urine as unchanged efavirenz.
Hepatic impairment: In a single-dose study, half life was doubled in the single patient with severe
hepatic impairment (Child Pugh Class C), indicating a potential for a much greater degree of
accumulation. A multiple-dose study showed no significant effect on efavirenz pharmacokinetics in
patients with mild hepatic impairment (Child-Pugh Class A) compared with controls. There were
insufficient data to determine whether moderate or severe hepatic impairment (Child-Pugh Class B or
C) affects efavirenz pharmacokinetics.
Gender, race, elderly: although limited data suggest that females as well as Asian and Pacific Island
patients may have higher exposure to efavirenz, they do not appear to be less tolerant of efavirenz.
Pharmacokinetic studies have not been performed in the elderly.
Paediatric population
In 49 paediatric patients receiving the equivalent of a 600 mg dose of efavirenz (dose adjusted from
calculated body size based on weight), steady state C max was 14.1 μM, steady state C min was 5.6 μM,
and AUC was 216 μM·h. The pharmacokinetics of efavirenz in paediatric patients were similar to
adults.
5.3 Preclinical safety data
Efavirenz was not mutagenic or clastogenic in conventional genotoxicity assays.
Efavirenz induced foetal resorptions in rats. Malformations were observed in 3 of 20 foetuses/
newborns from efavirenz-treated cynomolgus monkeys given doses resulting in plasma efavirenz
concentrations similar to those seen in humans. Anencephaly and unilateral anophthalmia with
secondary enlargement of the tongue were observed in one foetus, microophthalmia was observed in
another foetus, and cleft palate was observed in a third foetus. No malformations were observed in
foetuses from efavirenz-treated rats and rabbits.
Biliary hyperplasia was observed in cynomolgus monkeys given efavirenz for ≥ 1 year at a dose
resulting in mean AUC values approximately 2-fold greater than those in humans given the
recommended dose. The biliary hyperplasia regressed upon cessation of dosing. Biliary fibrosis has
been observed in rats. Non-sustained convulsions were observed in some monkeys receiving efavirenz
for ≥ 1 year, at doses yielding plasma AUC values 4- to 13-fold greater than those in humans given the
recommended dose (see sections 4.4 and 4.8).
Carcinogenicity studies showed an increased incidence of hepatic and pulmonary tumours in female
mice, but not in male mice. The mechanism of tumour formation and the potential relevance for
humans are not known.
Carcinogenicity studies in male mice, male and female rats were negative. While the carcinogenic
potential in humans is unknown, these data suggest that the clinical benefit of efavirenz outweighs the
potential carcinogenic risk to humans.
6.
PHARMACEUTICAL PARTICULARS
6.1 List of excipients
Capsule core
Sodium laurilsulfate
25
Lactose monohydrate
Magnesium stearate
Sodium starch glycolate
Capsule shell
Gelatine
Sodium laurilsulfate
Yellow iron oxide (E172)
Titanium dioxide (E171)
Silicon dioxide (E551)
Printing ink
Cochineal carminic acid (E120)
Indigo carmine (E132)
Titanium dioxide (E171)
6.2 Incompatibilities
Not applicable.
6.3 Shelf life
3 years.
6.4 Special precautions for storage
This medicinal product does not require any special storage conditions.
6.5 Nature and content of container
HDPE bottles with a child-resistant polypropylene closure. Each carton contains 1 bottle of 30 hard
capsules.
6.6 Special precautions for disposal
No special requirements.
7.
MARKETING AUTHORISATION HOLDER
Bristol-Myers Squibb Pharma EEIG
Uxbridge Business Park, Sanderson Road
Uxbridge UB8 1DH
United Kingdom
8.
MARKETING AUTHORISATION NUMBER(S)
EU/1/99/110/001 - bottle
9.
DATE OF FIRST AUTHORISATION/RENEWAL OF THE AUTHORISATION
Date of first authorisation: 28 May 1999
Date of latest renewal: 28 May 2009
26
10. DATE OF REVISION OF THE TEXT
Detailed information on this medicine is available on the European Medicines Agency web site:
http://www.ema.europa.eu/.
27
1.
NAME OF THE MEDICINAL PRODUCT
SUSTIVA 100 mg hard capsules
2.
QUALITATIVE AND QUANTITATIVE COMPOSITION
Each hard capsule contains 100 mg of efavirenz.
Excipient: each hard capsule contains 57.0 mg of lactose monohydrate.
For a full list of excipients, see section 6.1.
3.
PHARMACEUTICAL FORM
Hard capsule
White, printed with "SUSTIVA" on the body and "100 mg" on the cap.
4.
CLINICAL PARTICULARS
4.1 Therapeutic indications
SUSTIVA is indicated in antiviral combination treatment of human immunodeficiency virus-1
(HIV-1) infected adults, adolescents and children 3 years of age and older.
SUSTIVA has not been adequately studied in patients with advanced HIV disease, namely in patients
with CD4 counts < 50 cells/mm 3 , or after failure of protease inhibitor (PI) containing regimens.
Although cross-resistance of efavirenz with PIs has not been documented, there are at present
insufficient data on the efficacy of subsequent use of PI based combination therapy after failure of
regimens containing SUSTIVA.
For a summary of clinical and pharmacodynamic information, see section 5.1.
4.2 Posology and method of administration
Posology
Therapy should be initiated by a physician experienced in the management of HIV infection.
Concomitant antiretroviral therapy: SUSTIVA must be given in combination with other antiretroviral
medicines (see section 4.5).
It is recommended that SUSTIVA be taken on an empty stomach. The increased efavirenz
concentrations observed following administration of SUSTIVA with food may lead to an increase in
frequency of adverse reactions (see sections 4.4. and 5.2).
In order to improve the tolerability of nervous system undesirable effects, bedtime dosing is
recommended (see section 4.8).
Adults: the recommended dose of SUSTIVA in combination with nucleoside analogue reverse
transcriptase inhibitors (NRTIs) with or without a PI (see section 4.5) is 600 mg orally, once daily.
Dose adjustment: If SUSTIVA is coadministered with voriconazole, the voriconazole maintenance
dose must be increased to 400 mg every 12 hours and the SUSTIVA dose must be reduced by 50%,
28
i.e., to 300 mg once daily. When treatment with voriconazole is stopped, the initial dose of efavirenz
should be restored (see section 4.5).
If SUSTIVA is coadministered with rifampicin, an increase in the dose of SUSTIVA to 800 mg/day
may be considered (see section 4.5).
Special populations
Renal impairment: the pharmacokinetics of efavirenz have not been studied in patients with renal
insufficiency; however, less than 1% of an efavirenz dose is excreted unchanged in the urine, so the
impact of renal impairment on efavirenz elimination should be minimal (see section 4.4).
Hepatic impairment: patients with mild liver disease may be treated with their normally recommended
dose of efavirenz. Patients should be monitored carefully for dose-related adverse reactions, especially
nervous system symptoms (see sections 4.3 and 4.4).
Paediatric population (3 to 17 years)
The recommended dose of SUSTIVA in combination with a PI and/or NRTIs for patients between 3
and 17 years of age is described in Table 1. SUSTIVA hard capsules must only be administered to
children who are able to reliably swallow hard capsules. The safety and efficacy of SUSTIVA in
children below the age of 3 years or weighing less than 13 kg have not yet been established (see
sections 5.1 and 5.2).
Alternative method of administration: for children at least 3 years old and weighing at least 13 kg and
adults who cannot reliably swallow hard capsules, SUSTIVA oral solution is the preferred
formulation. Administration of the capsule contents with a small amount (1-2 teaspoons) of food may
be considered for patients who cannot tolerate the oral solution. In a palatability study in healthy
adults of efavirenz mixed with applesauce, grape jelly, yogurt, or infant formula, grape jelly received
the highest rating of good overall taste. Patients and caregivers must be instructed to open the capsule
carefully to avoid spillage or dispersion of the capsule contents into the air. It is recommended to hold
the capsule vertically with the cap facing up and to pull the cap away from the body of the capsule,
and to mix the capsule contents with food in a small container. The mixture should be administered as
soon as possible, but no more than 30 minutes after mixing. After administration of the efavirenz-food
mixture, an additional small amount (approximately 2 teaspoons) of food must be added to the empty
mixing container, stirred to disperse any remaining residue of the medicinal product, and administered
to the patient. No additional food should be consumed for up to 2 hours after administration of
efavirenz. There are limited safety and tolerability data for administration of the capsule contents in
paediatric patients.
Table 1
Paediatric dose to be administered once daily*
Body Weight SUSTIVA
kg Dose (mg)
13 to < 15 200
15 to < 20 250
20 to < 25 300
25 to < 32.5 350
32.5 to < 40 400
≥ 40 600
*For information on the bioavailability of the capsule
contents mixed with food vehicles, see section 5.2.
4.3 Contraindications
Hypersensitivity to the active substance or to any of the excipients.
29
 
Efavirenz must not be used in patients with severe hepatic impairment (Child Pugh Class C) (see
section 5.2).
Efavirenz must not be administered concurrently with terfenadine, astemizole, cisapride, midazolam,
triazolam, pimozide, bepridil, or ergot alkaloids (for example, ergotamine, dihydroergotamine,
ergonovine, and methylergonovine) because competition for CYP3A4 by efavirenz could result in
inhibition of metabolism and create the potential for serious and/or life-threatening undesirable effects
[for example, cardiac arrhythmias, prolonged sedation or respiratory depression] (see section 4.5).
Herbal preparations containing St. John’s wort (Hypericum perforatum) must not be used while taking
efavirenz due to the risk of decreased plasma concentrations and reduced clinical effects of efavirenz
(see section 4.5).
4.4 Special warnings and precautions for use
Efavirenz must not be used as a single agent to treat HIV or added on as a sole agent to a failing
regimen. As with all other non-nucleoside reverse transcriptase inhibitors (NNRTIs), resistant virus
emerges rapidly when efavirenz is administered as monotherapy. The choice of new antiretroviral
agent(s) to be used in combination with efavirenz should take into consideration the potential for viral
cross-resistance (see section 5.1).
Co-administration of efavirenz with the fixed combination tablet containing efavirenz, emtricitabine,
and tenofovir disoproxil fumarate is not recommended.
When prescribing medicinal products concomitantly with SUSTIVA, physicians should refer to the
corresponding Summary of Product Characteristics.
Patients should be advised that current antiretroviral therapy, including efavirenz, has not been proven
to prevent the risk of transmission of HIV to others through sexual contact or blood contamination.
Appropriate precautions should continue to be employed.
If any antiretroviral medicinal product in a combination regimen is interrupted because of suspected
intolerance, serious consideration should be given to simultaneous discontinuation of all antiretroviral
medicinal products. The antiretroviral medicinal products should be restarted at the same time upon
resolution of the intolerance symptoms. Intermittent monotherapy and sequential reintroduction of
antiretroviral agents is not advisable because of the increased potential for selection of resistant virus.
Rash: mild-to-moderate rash has been reported in clinical studies with efavirenz and usually resolves
with continued therapy. Appropriate antihistamines and/or corticosteroids may improve the tolerability
and hasten the resolution of rash. Severe rash associated with blistering, moist desquamation or
ulceration has been reported in less than 1% of patients treated with efavirenz. The incidence of
erythema multiforme or Stevens-Johnson syndrome was approximately 0.1%. Efavirenz must be
discontinued in patients developing severe rash associated with blistering, desquamation, mucosal
involvement or fever. If therapy with efavirenz is discontinued, consideration should also be given to
interrupting therapy with other antiretroviral agents to avoid development of resistant virus (see
section 4.8).
Experience with efavirenz in patients who discontinued other antiretroviral agents of the NNRTI class
is limited (see section 4.8). Efavirenz is not recommended for patients who have had a life-threatening
cutaneous reaction (e.g., Stevens-Johnson syndrome) while taking another NNRTI.
Psychiatric symptoms: psychiatric adverse reactions have been reported in patients treated with
efavirenz. Patients with a prior history of psychiatric disorders appear to be at greater risk of these
serious psychiatric adverse reactions. In particular, severe depression was more common in those with
a history of depression. There have also been post-marketing reports of severe depression, death by
suicide, delusions and psychosis-like behaviour. Patients should be advised that if they experience
30
symptoms such as severe depression, psychosis or suicidal ideation, they should contact their doctor
immediately to assess the possibility that the symptoms may be related to the use of efavirenz, and if
so, to determine whether the risks of continued therapy outweigh the benefits (see section 4.8).
Nervous system symptoms: symptoms including, but not limited to, dizziness, insomnia, somnolence,
impaired concentration and abnormal dreaming are frequently reported undesirable effects in patients
receiving efavirenz 600 mg daily in clinical studies (see section 4.8). Nervous system symptoms
usually begin during the first one or two days of therapy and generally resolve after the first 2 - 4
weeks. Patients should be informed that if they do occur, these common symptoms are likely to
improve with continued therapy and are not predictive of subsequent onset of any of the less frequent
psychiatric symptoms.
Seizures: convulsions have been observed in patients receiving efavirenz, generally in the presence of
known medical history of seizures. Patients who are receiving concomitant anticonvulsant medicinal
products primarily metabolised by the liver, such as phenytoin, carbamazepine and phenobarbital, may
require periodic monitoring of plasma levels. In a drug interaction study, carbamazepine plasma
concentrations were decreased when carbamazepine was co-administered with efavirenz (see
section 4.5). Caution must be taken in any patient with a history of seizures.
Hepatic events: a few of the postmarketing reports of hepatic failure occurred in patients with no pre-
existing hepatic disease or other identifiable risk factors (see section 4.8). Liver enzyme monitoring
should be considered for patients without pre-existing hepatic dysfunction or other risk factors.
Effect of food: the administration of SUSTIVA with food may increase efavirenz exposure (see
section 5.2) and may lead to an increase in the frequency of adverse reactions (see section 4.8). It is
recommended that SUSTIVA be taken on an empty stomach, preferably at bedtime.
Immune Reactivation Syndrome: in HIV infected patients with severe immune deficiency at the time
of institution of combination antiretroviral therapy (CART), an inflammatory reaction to
asymptomatic or residual opportunistic pathogens may arise and cause serious clinical conditions, or
aggravation of symptoms. Typically, such reactions have been observed within the first few weeks or
months of initiation of CART. Relevant examples are cytomegalovirus retinitis, generalised and/or
focal mycobacterial infections, and pneumonia caused by Pneumocystis jiroveci (formerly known as
Pneumocystis carinii ). Any inflammatory symptoms should be evaluated and treatment instituted
when necessary.
Lipodystrophy and metabolic abnormalities: combination antiretroviral therapy has been associated
with the redistribution of body fat (lipodystrophy) in HIV patients. The long-term consequences of
these events are currently unknown. Knowledge about the mechanism is incomplete. A connection
between visceral lipomatosis and PIs and lipoatrophy and NRTIs has been hypothesised. A higher risk
of lipodystrophy has been associated with individual factors such as older age, and with drug related
factors such as longer duration of antiretroviral treatment and associated metabolic disturbances.
Clinical examination should include evaluation for physical signs of fat redistribution. Consideration
should be given to the measurement of fasting serum lipids and blood glucose. Lipid disorders should
be managed as clinically appropriate (see section 4.8).
Osteonecrosis: although the etiology is considered to be multifactorial (including corticosteroid use,
alcohol consumption, severe immunosuppression, higher body mass index), cases of osteonecrosis
have been reported particularly in patients with advanced HIV-disease and/or long-term exposure to
combination antiretroviral therapy (CART). Patients should be advised to seek medical advice if they
experience joint aches and pain, joint stiffness or difficulty in movement.
Special populations:
Liver disease: efavirenz is contraindicated in patients with severe hepatic impairment (see sections 4.3
and 5.2) and not recommended in patients with moderate hepatic impairment because of insufficient
data to determine whether dose adjustment is necessary. Because of the extensive cytochrome
31
P450-mediated metabolism of efavirenz and limited clinical experience in patients with chronic liver
disease, caution must be exercised in administering efavirenz to patients with mild hepatic impairment.
Patients should be monitored carefully for dose-related adverse reactions, especially nervous system
symptoms. Laboratory tests should be performed to evaluate their liver disease at periodic intervals
(see section 4.2).
The safety and efficacy of efavirenz has not been established in patients with significant underlying
liver disorders. Patients with chronic hepatitis B or C and treated with combination antiretroviral
therapy are at increased risk for severe and potentially fatal hepatic adverse reactions. Patients with
pre-existing liver dysfunction including chronic active hepatitis have an increased frequency of liver
function abnormalities during combination antiretroviral therapy and should be monitored according to
standard practice. If there is evidence of worsening liver disease or persistent elevations of serum
transaminases to greater than 5 times the upper limit of the normal range, the benefit of continued
therapy with efavirenz needs to be weighed against the potential risks of significant liver toxicity. In
such patients, interruption or discontinuation of treatment must be considered (see section 4.8).
In patients treated with other medicinal products associated with liver toxicity, monitoring of liver
enzymes is also recommended. In case of concomitant antiviral therapy for hepatitis B or C, please
refer also to the relevant product information for these medicinal products.
Renal insufficiency : the pharmacokinetics of efavirenz have not been studied in patients with renal
insufficiency; however, less than 1% of an efavirenz dose is excreted unchanged in the urine, so the
impact of renal impairment on efavirenz elimination should be minimal (see section 4.2). There is no
experience in patients with severe renal failure and close safety monitoring is recommended in this
population.
Elderly patients : insufficient numbers of elderly patients have been evaluated in clinical studies to
determine whether they respond differently than younger patients.
Paediatric population :
Efavirenz has not been evaluated in children below 3 years of age or who weigh less than 13 kg.
Therefore, efavirenz should not be given to children less than 3 years of age.
Rash was reported in 26 of 57 children (46%) treated with efavirenz during a 48-week period and was
severe in three patients. Prophylaxis with appropriate antihistamines prior to initiating therapy with
efavirenz in children may be considered.
Lactose: patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or
glucose-galactose malabsorption should not take this medicinal product. Individuals with these
conditions may take efavirenz oral solution, which is free from lactose.
4.5 Interaction with other medicinal products and other forms of interaction
Efavirenz is an inducer of CYP3A4 and an inhibitor of some CYP450 isoenzymes including CYP3A4
(see section 5.2). Other compounds that are substrates of CYP3A4 may have decreased plasma
concentrations when co-administered with efavirenz. Efavirenz exposure may also be altered when
given with medicinal products or food (for example, grapefruit juice) which affect CYP3A4 activity.
Contraindications of concomitant use
Efavirenz must not be administered concurrently with terfenadine, astemizole, cisapride, midazolam,
triazolam, pimozide, bepridil, or ergot alkaloids (for example, ergotamine, dihydroergotamine,
ergonovine, and methylergonovine), since inhibition of their metabolism may lead to serious,
life-threatening events (see section 4.3).
St. John’s wort (Hypericum perforatum): co-administration of efavirenz and St. John’s wort or herbal
preparations containing St. John’s wort is contraindicated. Plasma levels of efavirenz can be reduced
32
by concomitant use of St. John’s wort due to induction of drug metabolising enzymes and/or transport
proteins by St. John’s wort. If a patient is already taking St. John’s wort, stop St. John’s wort, check
viral levels and if possible efavirenz levels. Efavirenz levels may increase on stopping St. John’s wort
and the dose of efavirenz may need adjusting. The inducing effect of St. John’s wort may persist for at
least 2 weeks after cessation of treatment. (see section 4.3).
Other interactions
Interactions between efavirenz and protease inhibitors, antiretroviral agents other than protease
inhibitors and other non-antiretroviral medicinal products are listed in Table 2 below (increase is
indicated as “↑”, decrease as “↓”, no change as “↔”, and once every 8 or 12 hours as “q8h” or
“q12h”). If available, 90% or 95% confidence intervals are shown in parentheses. Studies were
conducted in healthy subjects unless otherwise noted.
Table 2: Interactions between efavirenz and other medicinal products
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
ANTI-INFECTIVES
Antiretrovirals
Protease inhibitors (PI)
Atazanavir/ ritonavir/Efavirenz
(400 mg once daily/100 mg once
daily/600 mg once daily, all
administered with food)
Atazanavir (pm):
AUC: ↔* (↓9 to ↑10)
C max : ↑17%* (↑8 to ↑27)
C min : ↓42%* (↓31 to ↓51)
Co-administration of efavirenz
with atazanavir/ritonavir is not
recommended. If the co-
administration of atazanavir
with an NNRTI is required, an
increase in the dose of both
atazanavir and ritonavir to
400 mg and 200 mg,
respectively, in combination
with efavirenz could be
considered with close clinical
monitoring.
Atazanavir/ritonavir/Efavirenz
(400 mg once daily/200 mg once
daily/600 mg once daily, all
administered with food)
Atazanavir (pm):
AUC: ↔*/** (↓10 to ↑26)
C max : ↔*/** (↓5 to ↑26)
C min : ↑ 12%*/** (↓16 to ↑49)
(CYP3A4 induction).
* When compared to atazanavir
300 mg/ritonavir 100 mg once daily in
the evening without efavirenz. This
decrease in atazanavir C min might
negatively impact the efficacy of
atazanavir.
** based on historical comparison
Darunavir/ritonavir/Efavirenz
(300 mg twice daily*/100 mg
twice daily/600 mg once daily)
Darunavir:
AUC: ↓ 13%
C min : ↓ 31%
(CYP3A4 induction)
Efavirenz:
AUC: ↑ 21%
C min : ↑ 17%
(CYP3A4 inhibition)
The clinical significance of the
changes has not been
established. Similar findings are
expected with the approved
darunavir/ritonavir 600/100 mg
twice daily dose. This
combination should be used
with caution. See ritonavir row
below.
*lower than recommended dose
Fosamprenavir/ritonavir/Efavirenz
(700 mg twice daily/100 mg twice
daily/600 mg once daily)
No clinically significant
pharmacokinetic interaction
No dose adjustment is necessary
for any of these medicinal
products. See also ritonavir row
below.
Fosamprenavir/Nelfinavir/
Efavirenz
Interaction not studied.
No dose adjustment is necessary
for any of these medicinal
products.
Fosamprenavir/Saquinavir/
Efavirenz
Interaction not studied.
Not recommended as the
exposure to both PIs is expected
to be significantly decreased.
33
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
Indinavir/Efavirenz
(800 mg q8h/200 mg once daily)
Indinavir:
AUC : ↓ 31% (↓ 8 to ↓ 47)
C min : ↓ 40%
A similar reduction in indinavir
exposures was observed when indinavir
1000 mg q8h was given with efavirenz
600 mg daily.
(CYP3A4 induction)
Efavirenz:
No clinically significant
pharmacokinetic interaction
While the clinical significance
of decreased indinavir
concentrations has not been
established, the magnitude of
the observed pharmacokinetic
interaction should be taken into
consideration when choosing a
regimen containing both
efavirenz and indinavir.
Indinavir/ritonavir/Efavirenz
(800 mg twice daily/100 mg twice
daily/600 mg once daily)
Indinavir:
AUC: ↓ 25% (↓ 16 to ↓ 32) b
C max : ↓ 17% (↓ 6 to ↓ 26) b
C min : ↓ 50% (↓ 40 to ↓ 59) b
Efavirenz:
No clinically significant
pharmacokinetic interaction
The geometric mean C min for indinavir
(0.33 mg/l) when given with ritonavir
and efavirenz was higher than the mean
historical C min (0.15 mg/l) when
indinavir was given alone at 800 mg
q8h. In HIV-1 infected patients (n = 6),
the pharmacokinetics of indinavir and
efavirenz were generally comparable to
these uninfected volunteer data.
No dose adjustment is necessary
for efavirenz when given with
indinavir or indinavir/ritonavir.
See also ritonavir row below.
Lopinavir/ritonavir soft capsules or
oral solution/Efavirenz
Substantial decrease in lopinavir
exposure.
With efavirenz, an increase of
the lopinavir/ritonavir soft
capsule or oral solution doses
by 33% should be considered
(4 capsules/~6.5 ml twice daily
instead of 3 capsules/5 ml twice
daily). Caution is warranted
since this dose adjustment
might be insufficient in some
patients. The dose of
lopinavir/ritonavir tablets
should be increased to
500/125 mg twice daily when
co-administered with efavirenz
600 mg once daily.
See also ritonavir row below.
Lopinavir/ritonavir tablets/
Efavirenz
(400/100 mg twice daily/600 mg
once daily)
(500/125 mg twice daily/600 mg
once daily)
Lopinavir concentrations: ↓ 30-40%
Lopinavir concentrations: similar to
lopinavir/ritonavir 400/100 mg twice
daily without efavirenz
Nelfinavir/Efavirenz
(750 mg q8h/600 mg once daily)
Nelfinavir:
AUC: ↑ 20% (↑ 8 to ↑ 34)
C max : ↑ 21% (↑ 10 to ↑ 33)
The combination was generally well
tolerated.
No dose adjustment is necessary
for either medicinal product.
34
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
Ritonavir/Efavirenz
(500 mg twice daily/600 mg once
daily)
Ritonavir:
Morning AUC: ↑ 18% (↑ 6 to ↑ 33)
Evening AUC: ↔
Morning C max : ↑ 24% (↑ 12 to ↑ 38)
Evening C max : ↔
Morning C min : ↑ 42% (↑ 9 to ↑ 86) b
Evening C min : ↑ 24% (↑ 3 to ↑ 50) b
Efavirenz:
AUC: ↑ 21% (↑ 10 to ↑ 34)
C max : ↑ 14% (↑ 4 to ↑ 26)
C min : ↑ 25% (↑ 7 to ↑ 46) b
(inhibition of CYP-mediated oxidative
metabolism)
When efavirenz was given with
ritonavir 500 mg or 600 mg twice
daily, the combination was not well
tolerated (for example, dizziness,
nausea, paraesthesia and elevated liver
enzymes occurred). Sufficient data on
the tolerability of efavirenz with
low-dose ritonavir (100 mg, once or
twice daily) are not available.
When using efavirenz with
low-dose ritonavir, the
possibility of an increase in the
incidence of
efavirenz-associated adverse
events should be considered,
due to possible
pharmacodynamic interaction.
Saquinavir/ritonavir/Efavirenz
Interaction not studied.
No data are available to make a
dose recommendation. See also
ritonavir row above. Use of
efavirenz in combination with
saquinavir as the sole protease
inhibitor is not recommended.
CCR5 antagonist
Maraviroc/Efavirenz
(100 mg twice daily/600 mg once
daily)
Maraviroc:
AUC 12 : ↓ 45% (↓ 38 to ↓ 51)
C max : ↓ 51% (↓ 37 to ↓ 62)
Efavirenz concentrations not measured,
no effect is expected.
Refer to the Summary of
Product Characteristics for the
medicinal product containing
maraviroc.
Integrase strand transfer inhibitor
Raltegravir/Efavirenz
(400 mg single dose/ -)
Raltegravir:
AUC: ↓ 36%
C 12 : ↓ 21%
C max : ↓ 36%
(UGT1A1 induction)
No dose adjustment is necessary
for raltegravir.
NRTIs and NNRTIs
NRTIs/Efavirenz
Specific interaction studies have not
been performed with efavirenz and
NRTIs other than lamivudine,
zidovudine, and tenofovir disoproxil
fumarate. Clinically significant
interactions are not expected since the
NRTIs are metabolised via a different
route than efavirenz and would be
unlikely to compete for the same
metabolic enzymes and elimination
pathways.
No dose adjustment is necessary
for either medicinal product.
NNRTIs/Efavirenz
Interaction not studied.
Since use of two NNRTIs
proved not beneficial in terms
of efficacy and safety,
co-administration of efavirenz
35
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
and another NNRTI is not
recommended.
Antibiotics
Azithromycin/Efavirenz
(600 mg single dose/400 mg once
daily)
No clinically significant
pharmacokinetic interaction.
No dose adjustment is necessary
for either medicinal product.
Clarithromycin/Efavirenz
(500 mg q12h/400 mg once daily)
Clarithromycin:
AUC: ↓ 39% (↓ 30 to ↓ 46)
C max : ↓ 26% (↓ 15 to ↓ 35)
Clarithromycin 14-hydroxymetabolite:
AUC: ↑ 34% (↑ 18 to ↑ 53)
C max : ↑ 49% (↑ 32 to ↑ 69)
Efavirenz:
AUC: ↔
C max : ↑ 11% (↑ 3 to ↑ 19)
(CYP3A4 induction)
Rash developed in 46% of uninfected
volunteers receiving efavirenz and
clarithromycin.
The clinical significance of
these changes in clarithromycin
plasma levels is not known.
Alternatives to clarithromycin
(e.g. azithromycin) may be
considered. No dose adjustment
is necessary for efavirenz.
Other macrolide antibiotics
(e.g.,erythromycin)/Efavirenz
Interaction not studied.
No data are available to make a
dose recommendation.
Antimycobacterials
Rifabutin/Efavirenz
(300 mg once daily/600 mg once
daily)
Rifabutin:
AUC: ↓ 38% (↓ 28 to ↓ 47)
C max : ↓ 32% (↓ 15 to ↓ 46)
C min : ↓ 45% (↓ 31 to ↓ 56)
Efavirenz:
AUC: ↔
C max :
C min : ↓ 12% (↓ 24 to ↑ 1)
(CYP3A4 induction)
The daily dose of rifabutin
should be increased by 50%
when administered with
efavirenz. Consider doubling
the rifabutin dose in regimens
where rifabutin is given 2 or
3 times a week in combination
with efavirenz.
Rifampicin/Efavirenz
(600 mg once daily/600 mg once
daily)
Efavirenz:
AUC: ↓ 26% (↓ 15 to ↓ 36)
C max : ↓ 20% (↓ 11 to ↓ 28)
C min : ↓ 32% (↓ 15 to ↓ 46)
(CYP3A4 and CYP2B6 induction)
When taken with rifampicin,
increasing efavirenz daily dose
to 800 mg may provide
exposure similar to a daily dose
of 600 mg when taken without
rifampicin. The clinical effect
of this dose adjustment has not
been adequately evaluated.
Individual tolerability and
virological response should be
considered when making the
dose adjustment (see section
5.2). No dose adjustment is
necessary for rifampicin.
36
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
Antifungals
Itraconazole/Efavirenz
(200 mg q12h/600 mg once daily)
Itraconazole:
AUC: ↓ 39% (↓ 21 to ↓ 53)
C max : ↓ 37% (↓ 20 to ↓ 51)
C min : ↓ 44% (↓ 27 to ↓ 58)
(decrease in itraconazole
concentrations: CYP3A4 induction)
Hydroxyitraconazole:
AUC: ↓ 37% (↓ 14 to ↓ 55)
C max : ↓ 35% (↓ 12 to ↓ 52)
C min : ↓ 43% (↓ 18 to ↓ 60)
Efavirenz:
No clinically significant
pharmacokinetic change.
Since no dose recommendation
for itraconazole can be made,
alternative antifungal treatment
should be considered.
Posaconazole/Efavirenz
--/400 mg once daily
Posaconazole:
AUC: ↓ 50%
C max : ↓ 45%
(UDP-G induction)
Concomitant use of
posaconazole and efavirenz
should be avoided unless the
benefit to the patient outweighs
the risk.
Voriconazole/Efavirenz
(200 mg twice daily/400 mg once
daily)
Voriconazole:
AUC: ↓ 77%
C max : ↓ 61%
Efavirenz:
AUC: ↑ 44%
C max : ↑ 38%
Voriconazole:
AUC: ↓ 7% (↓ 23 to ↑ 13) *
C max : ↑ 23% (↓ 1 to ↑ 53) *
Efavirenz:
AUC: ↑ 17% (↑ 6 to ↑ 29) **
C max : ↔**
*compared to 200 mg twice daily alone
** compared to 600 mg once daily
alone
(competitive inhibition of oxidative
metabolism)
When efavirenz is co-
administered with voriconazole,
the voriconazole maintenance
dose must be increased to
400 mg twice daily and the
efavirenz dose must be reduced
by 50%, i.e., to 300 mg once
daily. When treatment with
voriconazole is stopped, the
initial dose of efavirenz should
be restored.
Voriconazole/Efavirenz
(400 mg twice daily/300 mg once
daily)
Fluconazole/Efavirenz
(200 mg once daily/400 mg once
daily)
No clinically significant
pharmacokinetic interaction
No dose adjustment is necessary
for either medicinal product.
Ketoconazole and other imidazole
antifungals
Interaction not studied
No data are available to make a
dose recommendation.
37
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
ACID REDUCING AGENTS
Aluminium hydroxide-magnesium
hydroxide-simethicone
antacid/Efavirenz
(30 ml single dose/400 mg single
dose)
Famotidine/Efavirenz
(40 mg single dose/400 mg single
dose)
Neither aluminium/magnesium
hydroxide antacids nor famotidine
altered the absorption of efavirenz.
Co-administration of efavirenz
with medicinal products that
alter gastric pH would not be
expected to affect efavirenz
absorption.
ANTIANXIETY AGENTS
Lorazepam/Efavirenz
(2 mg single dose/600 mg once
daily)
Lorazepam:
AUC: ↑ 7% (↑ 1 to ↑ 14)
C max : ↑ 16% (↑ 2 to ↑ 32)
These changes are not considered
clinically significant.
No dose adjustment is necessary
for either medicinal product.
ANTICOAGULANTS
Warfarin/Efavirenz
Interaction not studied. Plasma
concentrations and effects of warfarin
are potentially increased or decreased
by efavirenz.
Dose adjustment of warfarin
may be required.
ANTICONVULSANTS
Carbamazepine/Efavirenz
(400 mg once daily/600 mg once
daily)
Carbamazepine:
AUC: ↓ 27% (↓ 20 to ↓ 33)
C max : ↓ 20% (↓ 15 to ↓ 24)
C min : ↓ 35% (↓ 24 to ↓ 44)
Efavirenz:
AUC: ↓ 36% (↓ 32 to ↓ 40)
C max : ↓ 21% (↓ 15 to ↓ 26)
C min : ↓ 47% (↓ 41 to ↓ 53)
(decrease in carbamazepine
concentrations: CYP3A4 induction;
decrease in efavirenz concentrations:
CYP3A4 and CYP2B6 induction)
The steady-state AUC, C max and C min
of the active carbamazepine epoxide
metabolite remained unchanged.
Co-administration of higher doses of
either efavirenz or carbamazepine has
not been studied.
No dose recommendation can
be made. An alternative
anticonvulsant should be
considered. Carbamazepine
plasma levels should be
monitored periodically.
Phenytoin, Phenobarbital, and
other anticonvulsants that are
substrates of CYP450 isoenzymes
Interaction not studied. There is a
potential for reduction or increase in
the plasma concentrations of
phenytoin, phenobarbital and other
anticonvulsants that are substrates of
CYP450 isoenzymes when co-
administered with efavirenz.
When efavirenz is co-
administered with an
anticonvulsant that is a substrate
of CYP450 isoenzymes,
periodic monitoring of
anticonvulsant levels should be
conducted.
Valproic acid/Efavirenz
(250 mg twice daily/600 mg once
daily)
No clinically significant effect on
efavirenz pharmacokinetics. Limited
data suggest there is no clinically
significant effect on valproic acid
pharmacokinetics.
No dose adjustment is necessary
for efavirenz. Patients should be
monitored for seizure control.
38
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
Vigabatrin/Efavirenz
Gabapentin/Efavirenz
Interaction not studied. Clinically
significant interactions are not expected
since vigabatrin and gabapentin are
exclusively eliminated unchanged in
the urine and are unlikely to compete
for the same metabolic enzymes and
elimination pathways as efavirenz.
No dose adjustment is necessary
for any of these medicinal
products.
ANTIDEPRESSANTS
Selective Serotonin Reuptake Inhibitors (SSRIs)
Sertraline/Efavirenz
(50 mg once daily/600 mg once
daily)
Sertraline:
AUC: ↓ 39% (↓ 27 to ↓ 50)
C max : ↓ 29% (↓ 15 to ↓ 40)
C min : ↓ 46% (↓ 31 to ↓ 58)
Efavirenz:
AUC: ↔
C max : ↑ 11% (↑ 6 to ↑ 16)
C min : ↔
(CYP3A4 induction)
Sertraline dose increases should
be guided by clinical response.
No dose adjustment is necessary
for efavirenz.
Paroxetine/Efavirenz
(20 mg once daily/600 mg once
daily)
No clinically significant
pharmacokinetic interaction
No dose adjustment is necessary
for either medicinal product.
Fluoxetine/Efavirenz
Interaction not studied. Since
fluoxetine shares a similar metabolic
profile with paroxetine, i.e. a strong
CYP2D6 inhibitory effect, a similar
lack of interaction would be expected
for fluoxetine.
No dose adjustment is necessary
for either medicinal product.
ANTIHISTAMINES
Cetirizine/Efavirenz
(10 mg single dose/600 mg once
daily)
Cetirizine:
AUC: ↔
C max : ↓ 24% (↓ 18 to ↓ 30)
These changes are not considered
clinically significant.
Efavirenz:
No clinically significant
pharmacokinetic interaction
No dose adjustment is necessary
for either medicinal product.
39
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
CARDIOVASCULAR AGENTS
Calcium Channel Blockers
Diltiazem/Efavirenz
(240 mg once daily/600 mg once
daily)
Diltiazem:
AUC: ↓ 69% (↓ 55 to ↓ 79)
C max : ↓ 60% (↓ 50 to ↓ 68)
C min : ↓ 63% (↓ 44 to ↓ 75)
Desacetyl diltiazem:
AUC: ↓ 75% (↓ 59 to ↓ 84)
C max : ↓ 64% (↓ 57 to ↓ 69)
C min : ↓ 62% (↓ 44 to ↓ 75)
N-monodesmethyl diltiazem:
AUC: ↓ 37% (↓ 17 to ↓ 52)
C max : ↓ 28% (↓ 7 to ↓ 44)
C min : ↓ 37% (↓ 17 to ↓ 52)
Efavirenz:
AUC: ↑ 11% (↑ 5 to ↑ 18)
C max : ↑ 16% (↑ 6 to ↑ 26)
C min : ↑ 13% (↑ 1 to ↑ 26)
(CYP3A4 induction)
The increase in efavirenz
pharmacokinetic parameters is not
considered clinically significant.
Dose adjustments of diltiazem
should be guided by clinical
response (refer to the Summary
of Product Characteristics for
diltiazem). No dose adjustment
is necessary for efavirenz.
Verapamil, Felodipine, Nifedipine
and Nicardipine
Interaction not studied. When efavirenz
is co-administered with a calcium
channel blocker that is a substrate of
the CYP3A4 enzyme, there is a
potential for reduction in the plasma
concentrations of the calcium channel
blocker.
Dose adjustments of calcium
channel blockers should be
guided by clinical response
(refer to the Summary of
Product Characteristics for the
calcium channel blocker).
LIPID LOWERING MEDICINAL PRODUCTS
HMG Co-A Reductase Inhibitors
Atorvastatin/Efavirenz
(10 mg once daily/600 mg once
daily)
Atorvastatin:
AUC: ↓ 43% (↓ 34 to ↓ 50)
C max : ↓ 12% (↓ 1 to ↓ 26)
2-hydroxy atorvastatin:
AUC: ↓ 35% (↓ 13 to ↓ 40)
C max : ↓ 13% (↓ 0 to ↓ 23)
4-hydroxy atorvastatin:
AUC: ↓ 4% (↓ 0 to ↓ 31)
C max : ↓ 47% (↓ 9 to ↓ 51)
Total active HMG Co-A reductase
inhibitors:
AUC: ↓ 34% (↓ 21 to ↓ 41)
C max : ↓ 20% (↓ 2 to ↓ 26)
Cholesterol levels should be
periodically monitored. Dose
adjustment of atorvastatin may
be required (refer to the
Summary of Product
Characteristics for atorvastatin).
No dose adjustment is necessary
for efavirenz.
Pravastatin/Efavirenz
(40 mg once daily/600 mg once
daily)
Pravastatin:
AUC: ↓ 40% (↓ 26 to ↓ 57)
C max : ↓ 18% (↓ 59 to ↑ 12)
Cholesterol levels should be
periodically monitored. Dose
adjustment of pravastatin may
be required (refer to the
Summary of Product
Characteristics for pravastatin).
No dose adjustment is necessary
for efavirenz.
40
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
Simvastatin/Efavirenz
(40 mg once daily/600 mg once
daily)
Simvastatin:
AUC: ↓ 69% (↓ 62 to ↓ 73)
C max : ↓ 76% (↓ 63 to ↓ 79)
Simvastatin acid:
AUC: ↓ 58% (↓ 39 to ↓ 68)
C max : ↓ 51% (↓ 32 to ↓ 58)
Total active HMG Co-A reductase
inhibitors:
AUC: ↓ 60% (↓ 52 to ↓ 68)
C max : ↓ 62% (↓ 55 to ↓ 78)
(CYP3A4 induction)
Co-administration of efavirenz with
atorvastatin, pravastatin, or
simvastatin did not affect efavirenz
AUC or C max values.
Cholesterol levels should be
periodically monitored. Dose
adjustment of simvastatin may
be required (refer to the
Summary of Product
Characteristics for simvastatin).
No dose adjustment is necessary
for efavirenz.
Rosuvastatin/Efavirenz
Interaction not studied. Rosuvastatin is
largely excreted unchanged via the
faeces, therefore interaction with
efavirenz is not expected.
No dose adjustment is necessary
for either medicinal product.
HORMONAL CONTRACEPTIVES
Oral:
Ethinyloestradiol + Norgestimate/
Efavirenz
(0.035 mg + 0.25 mg once
daily/600 mg once daily)
Ethinyloestradiol:
AUC: ↔
C max : ↔
C min : ↓ 8% (↑ 14 to ↓ 25)
Norelgestromin (active metabolite):
AUC: ↓ 64% (↓ 62 to ↓ 67)
C max : ↓ 46% (↓ 39 to ↓ 52)
C min : ↓ 82% (↓ 79 to ↓ 85)
Levonorgestrel (active metabolite):
AUC: ↓ 83% (↓ 79 to ↓ 87)
C max : ↓ 80% (↓ 77 to ↓ 83)
C min : ↓ 86% (↓ 80 to ↓ 90)
(induction of metabolism)
Efavirenz: no clinically significant
interaction.
The clinical significance of these
effects is not known.
A reliable method of barrier
contraception must be used in
addition to hormonal
contraceptives (see section 4.6).
Injection: Depomedroxyprogesterone
acetate (DMPA)/Efavirenz
(150 mg IM single dose DMPA)
In a 3-month drug interaction study, no
significant differences in MPA
pharmacokinetic parameters were found
between subjects receiving efavirenz-
containing antiretroviral therapy and
subjects receiving no antiretroviral
therapy. Similar results were found by
other investigators, although the MPA
plasma levels were more variable in the
second study. In both studies, plasma
progesterone levels for subjects receiving
efavirenz and DMPA remained low
consistent with suppression of ovulation.
Because of the limited
information available, a reliable
method of barrier contraception
must be used in addition to
hormonal contraceptives (see
section 4.6).
Implant: Etonogestrel/Efavirenz
Interaction not studied. Decreased
exposure of etonogestrel may be
expected (CYP3A4 induction). There
have been occasional postmarketing
reports of contraceptive failure with
etonogestrel in efavirenz-exposed
patients.
A reliable method of barrier
contraception must be used in
addition to hormonal
contraceptives (see section 4.6).
41
 
Medicinal product by
therapeutic areas
(dose)
Effects on drug levels
Mean percent change in AUC, C max ,
C min with confidence intervals if
available a
(mechanism)
Recommendation concerning
co-administration with
efavirenz
IMMUNOSUPPRESSANTS
Immunosuppressants metabolized
by CYP3A4 (eg, cyclosporine,
tacrolimus, sirolimus)/Efavirenz
Interaction not studied. Decreased
exposure of the immunosuppressant
may be expected (CYP3A4 induction).
These immunosuppressants are not
anticipated to affect exposure of
efavirenz.
Dose adjustments of the
immunosuppressant may be
required. Close monitoring of
immunosuppressant
concentrations for at least 2
weeks (until stable
concentrations are reached) is
recommended when starting or
stopping treatment with
efavirenz.
OPIOIDS
Methadone/Efavirenz
(stable maintenance, 35-100 mg
once daily/600 mg once daily)
Methadone:
AUC: ↓ 52% (↓ 33 to ↓ 66)
C max : ↓ 45% (↓ 25 to ↓ 59)
(CYP3A4 induction)
In a study of HIV infected intravenous
drug users, co-administration of
efavirenz with methadone resulted in
decreased plasma levels of methadone
and signs of opiate withdrawal. The
methadone dose was increased by a
mean of 22% to alleviate withdrawal
symptoms.
Patients should be monitored
for signs of withdrawal and
their methadone dose increased
as required to alleviate
withdrawal symptoms.
Buprenorphine/naloxone/Efavirenz Buprenorphine:
AUC: ↓ 50%
Norbuprenorphine:
AUC: ↓ 71%
Efavirenz:
No clinically significant
pharmacokinetic interaction
Despite the decrease in
buprenorphine exposure, no
patients exhibited withdrawal
symptoms. Dose adjustment of
buprenorphine or efavirenz may
not be necessary when co-
administered.
a 90% confidence intervals unless otherwise noted.
b 95% confidence intervals.
Paediatric population
Interaction studies have only been performed in adults.
4.6 Fertility, pregnancy and lactation
Efavirenz should not be used during pregnancy unless there are no other appropriate treatment options.
Women of childbearing potential: pregnancy should be avoided in women treated with efavirenz.
Barrier contraception should always be used in combination with other methods of contraception (for
example, oral or other hormonal contraceptives). Because of the long half-life of efavirenz, use of
adequate contraceptive measures for 12 weeks after discontinuation of efavirenz is recommended.
Women of childbearing potential should undergo pregnancy testing before initiation of efavirenz.
Pregnancy: there are limited amount of data from the use of efavirenz in pregnant women. In
postmarketing experience through an antiretroviral pregnancy registry, outcomes for more than
400 pregnancies with first-trimester exposure to efavirenz as part of a combination antiretroviral
regimen have been prospectively reported with no specific malformation pattern observed. A small
number of cases of neural tube defects, including meningomyelocele, have been reported via the
registry. Most neural tube defects were isolated retrospectively reported cases, and causality cannot be
42
 
ruled out but has not been established. Studies in animals have shown reproductive toxicity including
marked teratogenic effects (see section 5.3).
Breastfeeding: studies in rats have demonstrated that efavirenz is excreted in milk reaching
concentrations much higher than those in maternal plasma. It is not known whether efavirenz is
excreted in human milk. Since animal data suggest that the substance may be passed into breast milk,
it is recommended that mothers taking efavirenz do not breast feed their infants. It is recommended
that HIV infected women do not breast feed their infants under any circumstances in order to avoid
transmission of HIV.
Fertility: the effect of efavirenz on male and female fertility in rats has only been evaluated at doses
that achieved systemic drug exposures equivalent to or below those achieved in humans given
recommended doses of efavirenz. In these studies, efavirenz did not impair mating or fertility of male
or female rats (doses up to 100 mg/kg/bid), and did not affect sperm or offspring of treated male rats
(doses up to 200 mg/bid). The reproductive performance of offspring born to female rats given
efavirenz was not affected.
4.7 Effects on ability to drive and use machines
Efavirenz may cause dizziness, impaired concentration, and/or somnolence. Patients should be
instructed that if they experience these symptoms they should avoid potentially hazardous tasks such
as driving or operating machinery.
4.8 Undesirable effects
a. Summary of the safety profile
Efavirenz has been studied in over 9,000 patients. In a subset of 1,008 adult patients who received
600 mg efavirenz daily in combination with PIs and/or NRTIs in controlled clinical studies, the most
frequently reported adverse reactions of at least moderate severity reported in at least 5% of patients
were rash (11.6%), dizziness (8.5%), nausea (8.0%), headache (5.7%) and fatigue (5.5%). The most
notable adverse reactions associated with efavirenz are rash and nervous system symptoms. Nervous
system symptoms usually begin soon after therapy onset and generally resolve after the first 2 - 4
weeks. Severe skin reactions such as Stevens-Johnson syndrome and erythema multiforme; psychiatric
adverse reactions including severe depression, death by suicide, and psychosis like behaviour; and
seizures have been reported in patients treated with efavirenz. The administration of SUSTIVA with
food may increase efavirenz exposure and may lead to an increase in the frequency of adverse
reactions (see section 4.4).
The long-term safety profile of efavirenz-containing regimens was evaluated in a controlled trial (006)
in which patients received efavirenz + zidovudine + lamivudine (n = 412, median duration
180 weeks), efavirenz + indinavir (n = 415, median duration 102 weeks), or indinavir + zidovudine +
lamivudine (n = 401, median duration 76 weeks). Long-term use of efavirenz in this study was not
associated with any new safety concerns.
b. Tabulated list of adverse reactions
Adverse reactions of moderate or greater severity with at least possible relationship to treatment
regimen (based on investigator attribution) reported in clinical trials of efavirenz at the recommended
dose in combination therapy (n = 1,008) are listed below. Also listed in italics are adverse reactions
observed post-marketing in association with efavirenz-containing antiretroviral treatment regimens.
Frequency is defined using the following convention: very common (≥ 1/10); common (≥ 1/100 to
< 1/10); uncommon (≥ 1/1,000 to < 1/100); rare (≥ 1/10,000 to < 1/1,000); or very rare (< 1/10,000).
Immune system disorders
uncommon
hypersensitivity
43
 
Psychiatric disorders
common
abnormal dreams, anxiety, depression,
insomnia*
uncommon
affect lability, aggression, confusional state,
euphoric mood, hallucination, mania,
paranoia, psychosis , suicide attempt, suicide
ideation*
rare
delusion , neurosis , completed suicide ‡, *
Nervous system disorders
common
cerebellar coordination and balance
disturbances , disturbance in attention
(3.6%), dizziness (8.5%), headache (5.7%),
somnolence (2.0%)*
uncommon
agitation, amnesia, ataxia, coordination
abnormal, convulsions, thinking abnormal,*
tremo r
Eye disorders
uncommon
vision blurred
Ear and labyrinth disorders
uncommon
tinnitus , vertigo
Vascular disorders
uncommon
flushing
Gastrointestinal disorders
common
abdominal pain, diarrhoea, nausea, vomiting
uncommon
pancreatitis
Hepatobiliary disorders
uncommon
hepatitis acute
rare
hepatic failure ‡, *
Skin and subcutaneous tissue disorders
very common
rash (11.6%)*
common
pruritus
uncommon
erythema multiforme, Stevens-Johnson
syndrome*
rare
photoallergic dermatitis
Reproductive system and breast disorders
uncommon
gynaecomastia
General disorders and administration site conditions
common
fatigue
* See section c. Description of selected adverse reactions for more details.
44
 
These adverse reactions were identified through post-marketing surveillance; however, the
frequencies were determined using data from 16 clinical trials (n=3,969).
These adverse reactions were identified through post-marketing surveillance but not reported as drug-
related events for efavirenz-treated patients in 16 clinical trials. The frequency category of "rare" was
defined per A Guideline on Summary of Product Characteristics (SmPC) (rev. 2, Sept 2009) on the
basis of an estimated upper bound of the 95% confidence interval for 0 events given the number of
patients treated with efavirenz in these clinical trials (n=3,969).
c. Description of selected adverse reactions
Rash: in clinical studies, 26% of patients treated with 600 mg of efavirenz experienced skin rash
compared with 17% of patients treated in control groups. Skin rash was considered treatment related in
18% of patients treated with efavirenz. Severe rash occurred in less than 1% of patients treated with
efavirenz, and 1.7% discontinued therapy because of rash. The incidence of erythema multiforme or
Stevens-Johnson syndrome was approximately 0.1%.
Rashes are usually mild-to-moderate maculopapular skin eruptions that occur within the first two
weeks of initiating therapy with efavirenz. In most patients rash resolves with continuing therapy with
efavirenz within one month. Efavirenz can be reinitiated in patients interrupting therapy because of
rash. Use of appropriate antihistamines and/or corticosteroids is recommended when efavirenz is
restarted.
Experience with efavirenz in patients who discontinued other antiretroviral agents of the NNRTI class
is limited. Reported rates of recurrent rash following a switch from nevirapine to efavirenz therapy,
primarily based on retrospective cohort data from published literature, range from 13 to 18%,
comparable to the rate observed in patients treated with efavirenz in clinical studies. (See section 4.4.)
Psychiatric symptoms: serious psychiatric adverse reactions have been reported in patients treated with
efavirenz. In controlled trials, the frequency of specific serious psychiatric events were:
Efavirenz regimen
(n=1,008)
Control regimen
(n=635)
- severe depression
1.6%
0.6%
- suicidal ideation
0.6%
0.3%
- non-fatal suicide attempts
0.4%
0%
- aggressive behaviour
0.4%
0.3%
- paranoid reactions
0.4%
0.3%
- manic reactions
0.1%
0%
Patients with a history of psychiatric disorders appear to be at greater risk of these serious psychiatric
adverse reactions with frequencies ranging from 0.3% for manic reactions to 2.0% for both severe
depression and suicidal ideation. There have also been post-marketing reports of death by suicide,
delusions and psychosis-like behaviour.
Nervous system symptoms: in clinical controlled trials, frequently reported adverse reactions included,
but were not limited to dizziness, insomnia, somnolence, impaired concentration and abnormal
dreaming. Nervous system symptoms of moderate-to-severe intensity were experienced by 19%
(severe 2%) of patients compared to 9% (severe 1%) of patients receiving control regimens. In clinical
studies 2% of patients treated with efavirenz discontinued therapy due to such symptoms.
Nervous system symptoms usually begin during the first one or two days of therapy and generally
resolve after the first 2 - 4 weeks. In a study of uninfected volunteers, a representative nervous system
symptom had a median time to onset of 1 hour post-dose and a median duration of 3 hours. Nervous
system symptoms may occur more frequently when efavirenz is taken concomitantly with meals
possibly due to increased efavirenz plasma levels (see section 5.2). Dosing at bedtime seems to
improve the tolerability of these symptoms and can be recommended during the first weeks of therapy
45
and in patients who continue to experience these symptoms (see section 4.2). Dose reduction or
splitting the daily dose has not been shown to provide benefit.
Analysis of long-term data showed that, beyond 24 weeks of therapy, the incidences of new-onset
nervous system symptoms among efavirenz-treated patients were generally similar to those in the
control arm.
Hepatic failure: A few of the postmarketing reports of hepatic failure, including cases in patients with
no pre-existing hepatic disease or other identifiable risk factors, were characterized by a fulminant
course, progressing in some cases to transplantation or death.
Immune Reactivation Syndrome: in HIV infected patients with severe immune deficiency at the time
of initiation of combination antiretroviral therapy (CART), an inflammatory reaction to asymptomatic
or residual opportunistic infections may arise (see section 4.4).
Lipodystrophy and metabolic abnormalities: combination antiretroviral therapy has been associated
with redistribution of body fat (lipodystrophy) in HIV patients including the loss of peripheral and
facial subcutaneous fat, increased intra-abdominal and visceral fat, breast hypertrophy and
dorsocervical fat accumulation (buffalo hump).
Combination antiretroviral therapy has been associated with metabolic abnormalities such as
hypertriglyceridaemia, hypercholesterolaemia, insulin resistance, hyperglycaemia and
hyperlactataemia (see section 4.4).
Osteonecrosis: cases of osteonecrosis have been reported, particularly in patients with generally
acknowledged risk factors, advanced HIV disease or long-term exposure to combination antiretroviral
therapy (CART). The frequency of this is unknown (see section 4.4).
Laboratory test abnormalities:
Liver enzymes : elevations of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) to
greater than five times the upper limit of the normal range (ULN) were seen in 3% of 1,008 patients
treated with 600 mg of efavirenz (5-8% after long-term treatment in study 006). Similar elevations
were seen in patients treated with control regimens (5% after long-term treatment). Elevations of
gamma-glutamyltransferase (GGT) to greater than five times ULN were observed in 4% of all patients
treated with 600 mg of efavirenz and 1.5-2% of patients treated with control regimens (7% of
efavirenz-treated patients and 3% of control-treated patients after long-term treatment). Isolated
elevations of GGT in patients receiving efavirenz may reflect enzyme induction. In the long-term
study (006), 1% of patients in each treatment arm discontinued because of liver or biliary system
disorders.
Amylase : in the clinical trial subset of 1,008 patients, asymptomatic increases in serum amylase levels
greater than 1.5 times the upper limit of normal were seen in 10% of patients treated with efavirenz
and 6% of patients treated with control regimens. The clinical significance of asymptomatic increases
in serum amylase is unknown.
Lipids : increases in total cholesterol of 10 - 20% have been observed in some uninfected volunteers
receiving efavirenz. In clinical trials of various efavirenz-containing regimens in treatment naive
patients, total cholesterol, HDL-cholesterol, and triglycerides increased over 48 weeks of treatment
(21 - 31%, 23 - 34%, and 23 - 49%, respectively). The proportion of patients with a total
cholesterol/HDL-cholesterol ratio greater than 5 was unchanged. The magnitude of changes in lipid
levels may be influenced by factors such as duration of therapy and other components of the
antiretroviral regimen.
Cannabinoid test interaction : efavirenz does not bind to cannabinoid receptors. False positive urine
cannabinoid test results have been reported in uninfected volunteers who received efavirenz. False
positive test results have only been observed with the CEDIA DAU Multi-Level THC assay, which is
46
used for screening, and have not been observed with other cannabinoid assays tested including tests
used for confirmation of positive results.
d. Paediatric population
Undesirable effects in children were generally similar to those of adult patients. Rash was reported
more frequently in children (in a clinical study including 57 children who received efavirenz during a
48-week period, rash was reported in 46%) and was more often of higher grade than in adults (severe
rash was reported in 5.3% of children). Prophylaxis with appropriate antihistamines prior to initiating
therapy with efavirenz in children may be considered. Although nervous system symptoms are
difficult for young children to report, they appear to be less frequent in children and were generally
mild. In the study of 57 children, 3.5% of patients experienced nervous system symptoms of moderate
intensity, predominantly dizziness. No child had severe symptoms or had to discontinue because of
nervous system symptoms.
e. Other special populations
Liver enzymes in hepatitis B or C co-infected patients : in the long-term data set from study 006,
137 patients treated with efavirenz-containing regimens (median duration of therapy, 68 weeks) and
84 treated with a control regimen (median duration, 56 weeks) were seropositive at screening for
hepatitis B (surface antigen positive) and/or C (hepatitis C antibody positive). Among these
co-infected patients in study 006, elevations in AST to greater than five times ULN developed in 13%
of efavirenz-treated patients and in 7% of controls, and elevations in ALT to greater than five times
ULN developed in 20% and 7%, respectively. Among co-infected patients, 3% of those treated with
efavirenz and 2% in the control arm discontinued because of liverdisorders (see section 4.4).
4.9 Overdose
Some patients accidentally taking 600 mg twice daily have reported increased nervous system
symptoms. One patient experienced involuntary muscle contractions.
Treatment of overdose with efavirenz should consist of general supportive measures, including
monitoring of vital signs and observation of the patient’s clinical status. Administration of activated
charcoal may be used to aid removal of unabsorbed efavirenz. There is no specific antidote for
overdose with efavirenz. Since efavirenz is highly protein bound, dialysis is unlikely to remove
significant quantities of it from blood.
5.
PHARMACOLOGICAL PROPERTIES
5.1 Pharmacodynamic properties
Pharmacotherapeutic group: Non-nucleoside reverse transcriptase inhibitors.
ATC code: J05AG03
Mechanism of action: efavirenz is a NNRTI of HIV-1. Efavirenz is a non-competitive inhibitor of
HIV-1 reverse transcriptase (RT) and does not significantly inhibit HIV-2 RT or cellular DNA
polymerases (α, β, γ or δ).
Antiviral activity: the free concentration of efavirenz required for 90 to 95% inhibition of wild type or
zidovudine-resistant laboratory and clinical isolates in vitro ranged from 0.46 to 6.8 nM in
lymphoblastoid cell lines, peripheral blood mononuclear cells (PBMCs) and macrophage/monocyte
cultures.
Resistance: the potency of efavirenz in cell culture against viral variants with amino acid substitutions
at positions 48, 108, 179, 181 or 236 in RT or variants with amino acid substitutions in the protease
was similar to that observed against wild type viral strains. The single substitutions which led to the
47
highest resistance to efavirenz in cell culture correspond to a leucine-to-isoleucine change at position
100 (L100I, 17 to 22-fold resistance) and a lysine-to-asparagine at position 103 (K103N, 18 to 33-fold
resistance). Greater than 100-fold loss of susceptibility was observed against HIV variants expressing
K103N in addition to other amino acid substitutions in RT.
K103N was the most frequently observed RT substitution in viral isolates from patients who
experienced a significant rebound in viral load during clinical studies of efavirenz in combination with
indinavir or zidovudine + lamivudine. This mutation was observed in 90% of patients receiving
efavirenz with virological failure. Substitutions at RT positions 98, 100, 101, 108, 138, 188, 190 or
225 were also observed, but at lower frequencies, and often only in combination with K103N. The
pattern of amino acid substitutions in RT associated with resistance to efavirenz was independent of
the other antiviral medications used in combination with efavirenz.
Cross resistance: cross resistance profiles for efavirenz, nevirapine and delavirdine in cell culture
demonstrated that the K103N substitution confers loss of susceptibility to all three NNRTIs. Two of
three delavirdine-resistant clinical isolates examined were cross-resistant to efavirenz and contained
the K103N substitution. A third isolate which carried a substitution at position 236 of RT was not
cross-resistant to efavirenz.
Viral isolates recovered from PBMCs of patients enrolled in efavirenz clinical studies who showed
evidence of treatment failure (viral load rebound) were assessed for susceptibility to NNRTIs. Thirteen
isolates previously characterised as efavirenz-resistant were also resistant to nevirapine and
delavirdine. Five of these NNRTI-resistant isolates were found to have K103N or a valine-to-
isoleucine substitution at position 108 (V108I) in RT. Three of the efavirenz treatment failure isolates
tested remained sensitive to efavirenz in cell culture and were also sensitive to nevirapine and
delavirdine.
The potential for cross resistance between efavirenz and PIs is low because of the different enzyme
targets involved. The potential for cross-resistance between efavirenz and NRTIs is low because of the
different binding sites on the target and mechanism of action.
Clinical efficacy:
Efavirenz has not been studied in controlled studies in patients with advanced HIV disease, namely
with CD4 counts < 50 cells/mm 3 , or in PI or NNRTI experienced patients. Clinical experience in
controlled studies with combinations including didanosine or zalcitabine is limited.
Two controlled studies (006 and ACTG 364) of approximately one year duration with efavirenz in
combination with NRTIs and/or PIs, have demonstrated reduction of viral load below the limit of
quantification of the assay and increased CD4 lymphocytes in antiretroviral therapy-naïve and
NRTI-experienced HIV-infected patients. Study 020 showed similar activity in NRTI-experienced
patients over 24 weeks. In these studies the dose of efavirenz was 600 mg once daily; the dose of
indinavir was 1,000 mg every 8 hours when used with efavirenz and 800 mg every 8 hours when used
without efavirenz. The dose of nelfinavir was 750 mg given three times a day. The standard doses of
NRTIs given every 12 hours were used in each of these studies.
Study 006, a randomized, open-label trial, compared efavirenz + zidovudine + lamivudine or
efavirenz + indinavir with indinavir + zidovudine + lamivudine in 1,266 patients who were required to
be efavirenz-, lamivudine-, NNRTI-, and PI-naive at study entry. The mean baseline CD4 cell count
was 341 cells/mm 3 and the mean baseline HIV-RNA level was 60,250 copies/ml. Efficacy results for
study 006 on a subset of 614 patients who had been enrolled for at least 48 weeks are found in Table 3.
In the analysis of responder rates (the non-completer equals failure analysis [NC = F]), patients who
terminated the study early for any reason, or who had a missing HIV-RNA measurement that was
either preceded or followed by a measurement above the limit of assay quantification were considered
to have HIV-RNA above 50 or above 400 copies/ml at the missing time points.
48
Table 3: Efficacy results for study 006
Responder rates (NC = F a )
Plasma HIV-RNA
Mean change
from
baseline-CD4
cell count
< 400 copies/ml
(95% C.I. b )
< 50 copies/ml
(95% C.I. b )
cells/mm 3
(S.E.M. c )
Treatment
Regimen d
n
48 weeks
48 weeks
48 weeks
EFV +
ZDV + 3TC
202
67%
(60%, 73%)
62%
(55%, 69%)
187
(11.8)
EFV + IDV 206
54%
(47%, 61%)
48%
(41%, 55%)
177
(11.3)
IDV +
ZDV + 3TC
206
45%
(38%, 52%)
40%
(34%, 47%)
153
(12.3)
a NC = F, noncompleter = failure.
b C.I., confidence interval.
c S.E.M., standard error of the mean.
d
EFV, efavirenz; ZDV, zidovudine; 3TC, lamivudine; IDV, indinavir.
Long-term results at 168 weeks of study 006 (160 patients completed study on treatment with
EFV+IDV, 196 patients with EFV+ZDV+3TC and 127 patients with IDV+ZDV+3TC, respectively),
suggest durability of response in terms of proportions of patients with HIV RNA < 400 copies/ml,
HIV RNA < 50 copies/ml and in terms of mean change from baseline CD4 cell count.
Efficacy results for studies ACTG 364 and 020 are found in Table 4. Study ACTG 364 enrolled
196 patients who had been treated with NRTIs but not with PIs or NNRTIs. Study 020 enrolled
327 patients who had been treated with NRTIs but not with PIs or NNRTIs. Physicians were allowed
to change their patient’s NRTI regimen upon entry into the study. Responder rates were highest in
patients who switched NRTIs.
Table 4: Efficacy results for studies ACTG 364 and 020
Responder rates (NC = F a )
Plasma HIV-RNA
Mean change from
baseline-CD4 cell
count
Study Number/
Treatment Regimens b
n
%
(95% C.I. c )
% (95% C.I.) cells/mm 3 (S.E.M. d )
Study ACTG 364
48 weeks
< 500 copies/ml
< 50 copies/ml
EFV + NFV + NRTIs
65 70
(59, 82)
---
---
107
(17.9)
EFV + NRTIs
65 58
(46, 70)
---
---
114
(21.0)
NFV + NRTIs
66 30
(19, 42)
---
---
94
(13.6)
Study 020
24 weeks
< 400 copies/ml
< 50 copies/ml
EFV + IDV + NRTIs
157 60
(52, 68)
49
(41, 58)
104
(9.1)
IDV + NRTIs
170 51
(43, 59)
38
(30, 45)
77
(9.9)
a NC = F, noncompleter = failure.
b EFV, efavirenz; ZDV, zidovudine; 3TC, lamivudine; IDV, indinavir; NRTI, nucleoside reverse transcriptase inhibitor;
NFV, nelfinavir.
c C.I., confidence interval for proportion of patients in response.
d S.E.M., standard error of the mean.
---, not performed.
49
 
Paediatric population: ACTG 382 is an ongoing uncontrolled study of 57 NRTI-experienced
paediatric patients (3 - 16 years) which characterises the pharmacokinetics, antiviral activity and safety
of efavirenz in combination with nelfinavir (20 - 30 mg/kg given three times a day) and one or more
NRTIs. The starting dose of efavirenz was the equivalent of a 600 mg dose (adjusted from calculated
body size based on weight). The response rate, based on the NC = F analysis of the percentage of
patients with plasma HIV-RNA < 400 copies/ml at 48 weeks was 60% (95%, C.I. 47, 72), and 53%
(C.I. 40, 66) based on percentage of patients with plasma HIV-RNA < 50 copies/ml. The mean CD4
cell counts were increased by 63 ± 34.5 cells/mm 3 from baseline. The durability of the response was
similar to that seen in adult patients.
5.2 Pharmacokinetic properties
Absorption: peak efavirenz plasma concentrations of 1.6 - 9.1 μM were attained by 5 hours following
single oral doses of 100 mg to 1,600 mg administered to uninfected volunteers. Dose related increases
in C max and AUC were seen for doses up to 1,600 mg; the increases were less than proportional
suggesting diminished absorption at higher doses. Time to peak plasma concentrations (3 - 5 hours)
did not change following multiple dosing and steady-state plasma concentrations were reached in
6 - 7 days.
In HIV infected patients at steady state, mean C max , mean C min , and mean AUC were linear with
200 mg, 400 mg, and 600 mg daily doses. In 35 patients receiving efavirenz 600 mg once daily, steady
state C max was 12.9 ± 3.7 μM (29%) mean ± S.D. (% C.V.), steady state C min was
5.6 ± 3.2 μM (57%), and AUC was 184 ± 73 μM·h (40%).
Effect of food: the bioavailability of a single 600 mg dose of efavirenz hard capsules in uninfected
volunteers was increased 22% and 17%, respectively, when given with a meal of high fat or normal
composition, relative to the bioavailability of a 600 mg dose given under fasted conditions (see
section 4.4).
Bioavailability of hard capsule contents mixed with food vehicles: in healthy adult subjects, the
efavirenz AUC when administered as the contents of three 200 mg hard capsules mixed with
2 teaspoons of certain food vehicles (applesauce, grape jelly, yogurt or infant formula) met
bioequivalency criteria for the AUC of the intact capsule formulation administered under fasted
conditions.
Distribution: efavirenz is highly bound (approximately 99.5 - 99.75%) to human plasma proteins,
predominantly albumin. In HIV-1 infected patients (n = 9) who received efavirenz 200 to 600 mg once
daily for at least one month, cerebrospinal fluid concentrations ranged from 0.26 to 1.19%
(mean 0.69%) of the corresponding plasma concentration. This proportion is approximately 3-fold
higher than the non-protein-bound (free) fraction of efavirenz in plasma.
Biotransformation: studies in humans and in vitro studies using human liver microsomes have
demonstrated that efavirenz is principally metabolised by the cytochrome P450 system to
hydroxylated metabolites with subsequent glucuronidation of these hydroxylated metabolites. These
metabolites are essentially inactive against HIV-1. The in vitro studies suggest that CYP3A4 and
CYP2B6 are the major isozymes responsible for efavirenz metabolism and that it inhibited
P450 isozymes 2C9, 2C19, and 3A4. In in vitro studies efavirenz did not inhibit CYP2E1 and
inhibited CYP2D6 and CYP1A2 only at concentrations well above those achieved clinically.
Efavirenz plasma exposure may be increased in patients with the homozygous G516T genetic variant
of the CYP2B6 isoenzyme. The clinical implications of such an association are unknown; however,
the potential for an increased frequency and severity of efavirenz-associated adverse events cannot be
excluded.
Efavirenz has been shown to induce P450 enzymes, resulting in the induction of its own metabolism.
In uninfected volunteers, multiple doses of 200 - 400 mg per day for 10 days resulted in a lower than
50
predicted extent of accumulation (22 - 42% lower) and a shorter terminal half-life compared with
single dose administration (see below).
Elimination: efavirenz has a relatively long terminal half-life of at least 52 hours after single doses and
40 - 55 hours after multiple doses. Approximately 14 - 34% of a radiolabelled dose of efavirenz was
recovered in the urine and less than 1% of the dose was excreted in urine as unchanged efavirenz.
Hepatic impairment: In a single-dose study, half life was doubled in the single patient with severe
hepatic impairment (Child Pugh Class C), indicating a potential for a much greater degree of
accumulation. A multiple-dose study showed no significant effect on efavirenz pharmacokinetics in
patients with mild hepatic impairment (Child-Pugh Class A) compared with controls. There were
insufficient data to determine whether moderate or severe hepatic impairment (Child-Pugh Class B or
C) affects efavirenz pharmacokinetics.
Gender, race, elderly: although limited data suggest that females as well as Asian and Pacific Island
patients may have higher exposure to efavirenz, they do not appear to be less tolerant of efavirenz.
Pharmacokinetic studies have not been performed in the elderly.
Paediatric population
In 49 paediatric patients receiving the equivalent of a 600 mg dose of efavirenz (dose adjusted from
calculated body size based on weight), steady state C max was 14.1 μM, steady state C min was 5.6 μM,
and AUC was 216 μM·h. The pharmacokinetics of efavirenz in paediatric patients were similar to
adults.
5.3 Preclinical safety data
Efavirenz was not mutagenic or clastogenic in conventional genotoxicity assays.
Efavirenz induced foetal resorptions in rats. Malformations were observed in 3 of 20 foetuses/
newborns from efavirenz-treated cynomolgus monkeys given doses resulting in plasma efavirenz
concentrations similar to those seen in humans. Anencephaly and unilateral anophthalmia with
secondary enlargement of the tongue were observed in one foetus, microophthalmia was observed in
another foetus, and cleft palate was observed in a third foetus. No malformations were observed in
foetuses from efavirenz-treated rats and rabbits.
Biliary hyperplasia was observed in cynomolgus monkeys given efavirenz for ≥ 1 year at a dose
resulting in mean AUC values approximately 2-fold greater than those in humans given the
recommended dose. The biliary hyperplasia regressed upon cessation of dosing. Biliary fibrosis has
been observed in rats. Non-sustained convulsions were observed in some monkeys receiving efavirenz
for ≥ 1 year, at doses yielding plasma AUC values 4- to 13-fold greater than those in humans given the
recommended dose (see sections 4.4 and 4.8).
Carcinogenicity studies showed an increased incidence of hepatic and pulmonary tumours in female
mice, but not in male mice. The mechanism of tumour formation and the potential relevance for
humans are not known.
Carcinogenicity studies in male mice, male and female rats were negative. While the carcinogenic
potential in humans is unknown, these data suggest that the clinical benefit of efavirenz outweighs the
potential carcinogenic risk to humans.
6.
PHARMACEUTICAL PARTICULARS
6.1 List of excipients
Capsule core
Sodium laurilsulfate
51
Lactose monohydrate
Magnesium stearate
Sodium starch glycolate
Capsule shell
Gelatine
Sodium laurilsulfate
Titanium dioxide (E171)
Silicon dioxide (E551)
Printing ink
Cochineal carminic acid (E120)
Indigo carmine (E132)
Titanium dioxide (E171)
6.2 Incompatibilities
Not applicable.
6.3 Shelf life
3 years.
6.4 Special precautions for storage
This medicinal product does not require any special storage conditions.
6.5 Nature and content of container
HDPE bottles with a child-resistant polypropylene closure. Each carton contains 1 bottle of 30 hard
capsules.
6.6 Special precautions for disposal
No special requirements.
7.
MARKETING AUTHORISATION HOLDER
Bristol-Myers Squibb Pharma EEIG
Uxbridge Business Park, Sanderson Road
Uxbridge UB8 1DH
United Kingdom
8.
MARKETING AUTHORISATION NUMBER(S)
EU/1/99/110/002 - bottle
9.
DATE OF FIRST AUTHORISATION/RENEWAL OF THE AUTHORISATION
Date of first authorisation: 28 May 1999
Date of latest renewal: 28 May 2009
52
10. DATE OF REVISION OF THE TEXT
Detailed information on this medicine is available on the European Medicines Agency web site:
http://www.ema.europa.eu/.
53
1.
Marketing Authorisation Holder
Bristol-Myers Squibb Pharma EEIG
Uxbridge Business Park, Sanderson Road
Uxbridge UB8 1DH
United Kingdom
Manufacturer
Bristol-Myers Squibb
Champ "Lachaud", La Goualle
F- 19250 Meymac
France
Bristol-Myers Squibb S.r.l.
Contrada Fontana del Ceraso
03012 Anagni (FR)
Italy
For any information about this medicine, please contact the local representative of the Marketing
Authorisation Holder.
Belgique/België/Belgien
Merck Sharp & Dohme B.V.
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Merck Sharp & Dohme B.V.
Succursale belge/Belgisch bijhuis
Tél/Tel: +32 (0) 800 38693
198
MSDBelgium_info@merck.com
MSDBelgium_info@merck.com
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199
Ιtalia
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This leaflet was last approved in
Detailed information on this medicine is available on the European Medicines Agency web site:
http://www.ema.europa.eu/.
200


Source: European Medicines Agency



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