This group of drugs was first developed during World War II because quinine, the standard treatment for malaria, was in short supply. Investigators discovered antimalarials could also be used to treat the joint pain that occurs with rheumatoid arthritis. Subsequent use of antimalarials showed that they are effective in controlling lupus arthritis, skin rashes, mouth ulcers, fatigue, and fever. They have also been shown to be effective in the treatment of discoid lupus erythematosus. Antimalarials are not used to manage more serious, systemic forms of SLE that affect the organs. It may be weeks or months before the patient notices that these drugs are controlling disease symptoms.

Types of Antimalarials

The drugs most often prescribed are hydroxychloroquine sulfate (Plaquenil®) and chloroquine (Aralen®).

Mechanism of Action and Use

The anti-inflammatory action of these drugs is not well understood. In some patients who take antimalarials, the total daily dose of corticosteroids can be reduced. Antimalarials also affect platelets to reduce the risk of blood clots and lower plasma lipid levels.

Side/Adverse Effects

Central Nervous System: headache, nervousness, irritability, dizziness, muscle weakness, and tinnitus

Gastrointestinal: nausea, vomiting, diarrhea, abdominal cramps, and loss of appetite

Ophthalmologic: Visual disturbances and retinal changes are manifested by blurring of vision and difficulty in focusing. A very serious potential side effect of antimalarial drugs is damage to the retina. Because of the relatively low doses used to treat SLE, the risk of retinal damage is quite small: about 1 in 5,000. However, patients should have a thorough eye examination before starting this treatment and yearly thereafter.

Dermatologic: dryness, pruritus, alopecia, skin and mucosal pigmentation, skin eruptions, and exfoliative dermatitis

Hematologic: blood dyscrasia and hemolysis in patients with glucose 6-phosphate dehydrogenase (G6PD) deficiency

Pregnancy

Antimalarials are usually continued during pregnancy. They do cross the placenta, but a clinical trial and case series have not found safety issues.

Considerations for Health Professionals Assessment: History: known allergies to the prescribed drugs, psoriasis, retinal disease, hepatic disease, alcoholism, pregnancy, and lactation Laboratory data: CBC, liver function tests, and G6PD deficiency Physical: all body systems to determine baseline data and alterations in function, skin color and lesions, mucous membranes, hair, reflexes, muscle strength, auditory and ophthalmologic screening, liver palpation, and abdominal examination Evaluation: therapeutic response and side effects Administration: before or after meals at the same time each day to maintain drug levels Teaching Points: See Patient Information Sheet on Antimalarials.

Source: National Institutes of Health, U.S.Dept of Health and Human Services