NARCOTICS (Gr. vapxcortKc 1, making numb), a general term for substances having the physiological action, in a healthy animal, of producing lethargy or stupor, which may pass into state of profound coma or unconsciousness along with complete paralysis, terminating in death. Certain substances of this class are used in medicine for the relief of pain, and are then called anodynes, whilst another group produce profound sleep, and are consequently known as hypnotics. In one sense, anaesthetics, such as chloroform and ether, may be held to be narcotics, but, as they are usually volatile substances causing unconsciousness for a comparatively short time, they are conveniently separated from the true narcotics, the effects of which are much more lasting. These distinctions are to a great extent artificial, as it is evident that a substance capable of producing partial insensibility to pain, or sleep, will inevitably in larger doses cause profound coma ending in death. Hence we find the same substances sometimes classed as anodynes and at other times as hypnotics. For example, small doses of opium, or of one or other of its preparations, relieve pain, whilst larger doses act as hypnotics, causing deep sleep passing into coma. Cannabis Indica, belladonna and hyoscyamus, are also anodyne in their action. The chief narcotics are mentioned below.
Opium is the inspissated juice of the Papaver somnifericm, containing 7.5 to 105% of anhydrous morphine. Besides morphine some of the other alkaloids contained in it are of a narcotic nature, notably papaverine, narceine, meconine, cryptopine and narcotine, but the principal anodyne and narcotic effects are due to the morphine alkaloid. Though seasoned opium takers may take 20 to 30 grs. without noticeable effects, I to 3 grs. produces marked symptoms in the western races. Idiosyncrasy is marked in regard tar the amount of opium a person can safely take. The medicinal dose is up to 2 grs., and the smallest dose that has been known to cause death in an adult is z gr. The narcotic properties of Morphine vary as to whether it is taken by the stomach or injected under the skin; 2 grs. by the stomach is dangerous, and a safe medicinal dose by the skin is a to s gr. The smallest dose that has produced death in an adult was 4 gr. given hypodermically. The motor centres of the brain and spinal cord are first stimulated by opium and morphine and later depressed; death in fatal cases being from paralysis of the respiratory centre of the medulla. For the treatment of poisoning see under Opium.
Cannabis indica or Indian Hemp (see Hemp). - The part used in medicine is the non-fertilized female spikes of the Cannabis sativa. The active constituent is the resin containing cannabin with the active principle cannabinol, the alkaloids cannabinene and tetanocanabine. Cannabis indica is sold in the East under various names. A confection of the drug made in Arabia is called hashisch. Churrus is the resin scraped off the leaves, and the dried leaf is called bang, gunga or ganga being the name given to the dried flowering tops sold for smoking. The medicinal dose is 4 to i gr. of the extract, 2 to 3 grs. is a poisonous dose, but there is no recorded fatal case in man. In Eastern countries the smoking of Cannabis indica produces a form of mania. The effects of smaller doses are intoxication of a pleasant character, exaltation, hallucinations and delirium, later dilatation of the pupils, drowsiness, sleep and coma. Indian hemp is an uncertain anodyne and hypnotic. When large quantities have been taken an emetic should be given or the stomach pump used, and endeavour to allay excitement until the effects have passed off.
The leaves of the Atropa Belladonna or deadly nightshade of which the active principle is atropine principally used as a sulphate. A small dose of belladonna or atropine causes dryness of the throat and mouth, dilatation of the pupils, dimness of vision except for distant objects and often double vision. The pulse becomes quick, rising, in an adult, from 80 to 120 or 160 beats per minute; and there is often a bright red flush over the skin. The intellectual powers are at first acute and strong, but they soon become confused. There is giddiness, confusion of thought, excitement, a peculiar talkative wakeful restiveness, in which the person shows that his mind is occupied by a train of fancies or is haunted by visions and spectres. Often there is violent delirium before sleep comes on. The sleep after a large dose deepens into stupor, with great muscular prostration or paralysis. During all the time the pupils are widely dilated. Death occurs from failure both of the heart's action and of respiration. The minimum lethal dose is not known, but 80 grs. of the root have caused death; i i o to lb gr. hypodermically have caused dangerous symptoms and z gr. would almost certainly be fatal. For the medicinal preparations and treatment of poisoning see Belladonna.
The part of the plant used is the leaves and seed of the Datura Stramonium or thorn apple, the alkaloidal constituent being daturine, a variable mixture of hyoscine and atropine. The physiological action is almost identical with belladonna. Poisoning is usually due to children eating the seeds; the lethal dose is unknown. The symptoms produced are divided into three stages - delirium, sleep and deep coma. In case of slight poisoning a rash is one of the toxic symptoms. The treatment of poisoning is to give emetics, wash out the stomach and give stimulants and pilocarpine subcutaneously, also to apply warmth and to use artificial respiration if necessary.
Hyoscyamus, the leaves of the,Hyoscyamus niger onhenbane (q.v.). The active principle is hyoscyamine. The physiological action is almost similar to belladonna, with excitement and cardiac stimulation and afterwards depression and stupor, but the action of hyoscyamus on the heart is more powerful. In large doses it is a strong cerebral depressant, and produces dilatation of the pupil; s gr. of hyoscamine produces marked effects, sleepiness and dryness of the mouth; a gr. by subcutaneous injection has produced fatal results. The treatment of hyoscyamus poisoning is similar to that of stramonium.
Hops (the Humulus Lupulus), containing the active principle lupuline, and Lactucarium, the juice of the Lactuca virosa (lettuce), containing an alkaloid lactucine, are very feeble narcotics, causing heaviness and sleep if taken in large doses.
Chloral Hydrate is a pure hypnotic which in larger doses is a powerful narcotic, producing prolonged sleep with depression of the cardiac and motor centres. It is an intrinsic cardiac poison, the heart being arrested in diastole, with coincident respiratory failure. Chloral hydrate is not uniform in its action, some people manifesting great susceptibility to the drug. It is safe in small doses of io to 20 grs. It is difficult to say what is a lethal dose. Cases are recorded of recovery after 336 grs. taken with an equal amount of potassium bromide and even after a dose of 595 grs., but in susceptible persons 10 to 15 grs. have produced toxic symptoms and death has occurred after doses of from 30 to 45 grs. If seen early, the treatment is an emetic, but if the poison should have been already absorbed, stimulants, hot coffee, strychnine or digitalin hypodermically, with perhaps artificial respiration, may be required.
Alcohol in large quantities is a strong narcotic, producing the typical stages of preliminary excitement followed by drowsiness and profound coma, during which death may occur. The treatment is washing out the stomach to prevent the absorption of the poison and the use of strychnine hypodermically.
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