Apomorphine

Apomorphine, Apomorphinum, C₁₇H₁₇NO₂. The hydrochloride salt of A., C₁₇H₁₇NO₂HCl, white or grayish crystals, soluble in 50 parts water, in 20 parts alcohol; insoluble in ether and chloroform. Aqueous solutions of A. are colorless; upon storage they take on a greenish and dark green color and gradually lose their effect on the organism. A. is obtained by the removal of an H₂O particle from morphine by heating morphine with HCl in a sealed tube to 140°. When administered subcutaneously in a dose of 0.005, A. causes in animals and humans nausea and vomiting 2-5 minutes after administration. When taken orally, A. causes vomiting only at doses 10-20 times larger, not earlier than half an hour after administration. The mechanism of the emetic action of A. is based on its stimulating effect on the vomiting center. In small doses, A., like other emetics, enhances the secretory activity of the mucous membrane of the respiratory tract and is used as an expectorant. When toxic doses of A. are used in animals, marked excitation of the central nervous system is observed, especially of the medulla oblongata, increased respiration and convulsions, followed by depression and paralysis of the striated muscles, cardiac muscle, and nervous system. As an emetic, the highest dose of A. is 0.005 subcutaneously; as an expectorant it is prescribed per os in doses of 0.001-0.005 in drops, mixtures, and pills.