This section is from the book "Botanic Drugs Their Materia Medica, Pharmacology and Therapeutics", by Thomas S. Blair. Also available from Amazon: Botanic Drugs, Their Materia Medica, Pharmacology and Therapeutics.
Johimbin. This drug is nowhere official, but has an extensive literature. The drug is asserted to be a potent aphrodisiac, a sexual stimulant useful in the treatment of neurasthenic impotence. Yohim-bin, the alkaloid, is locally anesthetic. The hydrochloride of the alkaloid is given in doses of 1-10 grain.