Yohimbine

Absorption

Rapidly absorbed following oral administration. Bioavailability is highly variable, ranging from 7 to 87% (mean 33%).

Description

Yohimbine is a natural alkaloid. It was first extracted from the barks of Corynanthe yohimbe, a species of Rubiaceae trees in West Africa. It was reported that, in the dried bark of Pausinystalia johimbe, the content of mixed alkaloids is higher than 6.1%, in which the main component is yohimbine, indicating a great prospect for development . Yohimbe bark has been used as an aphrodisiac in Africa since ancient times. In 1900, it was applied by Kowit and Muller to patients with impotence and paralytic insensitivity caused by neurasthenia and obtained curative effect. From then on, clinical application of yohimbine began. Currently, yohimbine is a pure plant preparation in the treatment of erectile dysfunction with more affirmation and more applications.

Description

Yohimbine is an indole alkaloid ester first identified in several herbal species by the American botanist R. Raymond-Hamet in 1934. Today its main sources are the African evergreen yohimbe (Pausinystalia yohimbe) and Indian snakeroot (Rauwolfia serpentina). Yohimbe bark is sold over the counter as an herbal aphrodisiac. Yohimbine hydrochloride is a prescription drug that has been used to treat erectile dysfunction with varying results.

The Uses of Yohimbine

Yohimbine occurs in Corinanthe johimbeK. and Rubiaceae trees. It is also foundin the roots of Rauwolfia serpentina L.and Apocyanaceae. Its derivatives areused therapeutically as adrenergic blockingagents.

Background

A plant alkaloid with alpha-2-adrenergic blocking activity. Yohimbine has been used as a mydriatic and in the treatment of impotence. It is also alleged to be an aphrodisiac.

Indications

Indicated as a sympatholytic and mydriatic. Impotence has been successfully treated with yohimbine in male patients with vascular or diabetic origins and psychogenic origins.

Pharmacokinetics

Yohimbine is an indolalkylamine alkaloid with chemical similarity to reserpine. Yohimbine blocks presynaptic alpha-2 adrenergic receptors. Its action on peripheral blood vessels resembles that of reserpine, though it is weaker and of short duration. Yohimbine's peripheral autonomic nervous system effect is to increase parasympathetic (cholinergic) and decrease sympathetic (adrenergic) activity. It is to be noted that in male sexual performance, erection is linked to cholinergic activity and to alpha-2 adrenergic blockade which may theoretically result in increased penile inflow, decreased penile outflow or both. Yohimbine exerts a stimulating action on the mood and may increase anxiety. Such actions have not been adequately studied or related to dosage although they appear to require high doses of the drug. Yohimbine has a mild anti-diuretic action, probably via stimulation of hypothalmic center and release of posterior pituitary hormone. Reportedly Yohimbine exerts no significant influence on cardiac stimulation and other effects mediated by (beta)-adrenergic receptors. Its effect on blood pressure, if any, would be to lower it; however, no adequate studies are at hand to quantitate this effect in terms of Yohimbine dosage.

Metabolism

Yohimbine appears to undergo extensive metabolism in an organ of high flow such as the liver or kidney, however, the precise metabolic fate of yohimbine has not been fully determined.