Atropina, B.P. Atropine.
C17H23NO3 = 289.194.
Atropine, C17H23NO3, may be obtained from the leaves or root of Atropa Belladonna, Linn. (N.O. Solanaceae); it is also found in other Solanaceous plants, and is more often obtained from the rhizome of Scopola carniolica, Jacq. (N.O. Solanaceae). It is also official in the U.S.P. It occurs in colourless, acicular crystals, or as a micro-crystalline powder. Melting-point, when pure, 115.5°. Commercial atropine frequently contains small amounts of hyoscyamine, the presence of which lowers the melting-point of the alkaloid and raises that of the aurichloride; atropine aurichloride may be prepared by adding gold chloride to a solution of the alkaloid in hydrochloric acid, and, after drying, should have a melting-point of 137°; while hyoscyamine aurichloride melts at 160°. Solutions of atropine are optically inactive, while solutions of hyoscyamine are optically active.
Soluble in water (1 in 500), alcohol (1 in 3), chloroform, or ether.
Action and Uses.—Atropine has a stimulant action on the central nervous system, especially on the motor area; and it depresses, and in large doses paralyses, the nerve-endings to secretory glands, plain muscle, and the heart. Applied locally to the skin it is used to check excessive perspiration, and to diminish the secretion of milk; also to depress sensory nerve-endings and so soothe chronic pain. Taken internally, it is also employed to arrest the secretions, especially of the sweat-glands in the night-sweats of phthisis, and, to a less degree, of milk and saliva. It is also employed for its action on the heart in any condition in which there is excessive nervous inhibition, whether this be due to disease or poisons such as digitalis; in all such conditions atropine accelerates the pulse by paralysing the vagus terminals. In ophthalmic practice it is used to dilate the pupil, the mydriasis produced being also accompanied by disturbance of accommodation. When such dilatation is necessary and there is reason to apprehend intra-ocular tension from glaucoma or other cause, homatropine should be preferred, as its action is so easily controlled by physostigmine. In virtue of its depressant effect on nerve-endings to plain muscle, atropine is employed in various forms of intestinal colic; it is also useful in the reduction of hernias, and is commonly administered with purgatives in order to lessen griping. In spasmodic contraction of the ureters, bile ducts, or urethra, whether produced by calculi or other causes, atropine is useful. A hypodermic injection of atropine will always abort an attack of spasmodic asthma, and these attacks cannot take place whilst the patient is under the influence of this drug. Atropine is used as a stimulant in conditions of cerebral and medullary depression—for example, in opium and other forms of narcotic poisoning. In whooping cough and other respiratory troubles it is possible that it acts beneficially by removing spasm rather than by exciting the respiratory centre. It has no action on glands which are not innervated, e.g., the kidney, pancreas, and milk, in spite of the fact that it still forms the routine treatment when it is desired to stop the flow of milk. The alkaloid is administered in the form of pills, prepared by trituration with milk sugar and massing with glucose. It is also used in preparations having a fatty basis in which the pure alkaloid is soluble with gentle heat. A solution in oleic acid and olive oil (Oleinatum Atropinae) is used as a pigment; a solution in castor oil (1 in 100) is employed for instillation into the eyes, and a solution in soft paraffin (1 in 100) made by gently heating, is also used in ophthalmic work. In cases of poisoning by atropine, the antidotes described under Atropine Sulphate should be employed.
Dose.—1/3 to 2/3 milligram (1/200 to 1/100 grain).
- Cereoli Atropinae, B.P.C.—ATROPINE URETHRAL BOUGIES. 1/60 grain.
- Chloroformum Atropinae, B.P.C.—CHLOROFORM OF ATROPINE. 1 in 200.
- This preparation is an improvement upon and has the same uses as Chloroformum Belladonnae, which is of somewhat uncertain alkaloidal strength.
- Collodium Atropinae, B.P.C.—ATROPINE COLLODION. 1 in 200.
- Atropine collodion is a colourless substitute for belladonna collodion, suitable for application to exposed parts. It allays the irritation of chilblains.
- Oculentum Atropinae, B.P.C.—ATROPINE EYE OINTMENT. 1 per cent.
- Used in ophthalmic practice to dilate the pupil; it should be applied to the eyes with a glass rod.
- Oculentum Atropinae cum Cocaina, B.P.C.—ATROPINE EYE OINTMENT WITH COCAINE.
- Atropine, 1 per cent.; cocaine, 2 per cent. This preparation should be applied to the eyes with a glass rod.
- Oleinatum Atropinae, B.P.C.—OLEINATE OF ATROPINE. Syn.—Oleatum Atropinae; Oleate of Atropine. 1 in 50.
- Readily absorbed by the skin; useful to paint on painful parts.
- Unguentum Atropinae, B.P.—ATROPINE OINTMENT.
- Atropine, 2; oleic acid, by weight, 8; lard, 90. Atropine ointment is applied to relieve neuralgic pain. It is not used for ophthalmic purposes.
The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.