Synonyms.—Woorara; Woorari; Woorali; Ourari; Urari.
Curare is an extract made from the bark of Strychnos toxifera, Schomb., and other species of Strychnos (N.O. Loganiaceae), probably mixed with other, possibly inert, substances. It is prepared as an arrow poison by tribes of Indians in British Guiana, French Guiana, Venezuela, Northern Brazil, and the United States of Colombia. The manner in which it is prepared is not exactly known, but an infusion or decoction is probably made, evaporated to a suitable consistence, and poured into gourds, bamboos, or earthen pots. The drug varies considerably. It was formerly obtained as a thick syrup, but it now occurs in commerce as a brittle blackish extract resembling black catechu in appearance, and often containing small cavities. When imported in bamboo it is dark brown and granular, and frequently exhibits small crystals. It has no odour, but a very bitter taste.
Constituents.—The constituents and strength of the drug vary in the different specimens. Gourd curare contains the poisonous alkaloid curarine, C19H26N2O, which has been obtained as a yellowish-brown powder with a bitter taste; curine, C18H19NO3, which is less poisonous than curarine, has also been obtained from gourd curare. Bamboo (tube) curare from the Amazon contains the alkaloids tubocurarine and curine, and pot curare the alkaloids protocurarine, protocurine, and protocuridine. Bamboo curare yields about 84 to 88 per cent. to water; gourd curare, 34 to 75 per cent.; pot curare 50 to 87 per cent. Gourd curare no longer occurs in commerce.
Action and Uses.—The principal effect of curare is to paralyse the motor nerve-endings in striped muscle, death occurring from respiratory failure. In larger doses it also paralyses nerve cells. Curare is almost inert when taken by the mouth, probably owing to its rapid excretion and to the destructive action of the gastric juice. It is used medicinally by hypodermic injection as Injectio Curarae Hypodermica in the treatment of tetanus, hydrophobia, and strychnine poisoning, but the dose is never pushed to the stage of motor paralysis, because efficient artificial respiration is so difficult to attain. Different specimens vary in strength, and physiologically tested curare should alone be used in the preparation of the injection, which should be used with great caution.
Dose.—3 to 30 milligrams (1/20 to ½ grain).
- Injectio Curarae Hypodermica, B.P.C.—HYPODERMIC INJECTION OF CURARE.
- Curare, in powder, 10 per cent. Dose.—6 to 36 centimils (0.06 to 0.36 milliliters) (1 to 6 minims).