Acidum Agaricum. Agaric Acid.
Related entry: Agaric
C_H40O7, 1 ½ H2O = 443.344.
Agaric acid, C19H36OH(COOH)3, 1 ½ H2O, is obtained from Polyporus officinalis (N.O. Hymenomycetes), a fungus growing on larch trees. It occurs as a nearly white, micro-crystalline powder, which is almost odourless and tasteless. Some impure samples of agaric acid have a yellowish colour. Melting-point, 140°. The acid should dissolve in boiling water to form a perfectly clear, foaming liquid.
Slightly soluble in water, in alcohol (1 in 130); solutions in caustic alkalies froth freely.
Action and Uses.— Agaric acid paralyses the nerve terminations in the sweat-glands, and is therefore valuable for stopping the night-sweats in phthisis. It is superior to atropine in that it does not cause dryness of the mouth and throat, and has little effect on the pupil of the eye. Commercial agaric acid varies in strength, and initial doses should be small. It is absorbed slowly, and the dose should therefore be taken some hours before retiring. Agaric acid may be administered in pills or cachets; as large doses have a purgative action, some preparation of opium is frequently added. It should not be administered hypodermically, as it causes intense pain and inflammation at the seat of injection.
Dose.—½ to 6 centigrams (1/12 to 1 grain).