Yohimbine

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Other Names

Aphrodin, corymbin, corynin, hydroergotocin,

johimbin, quebrachin, quebrachina, yohimbenin,

N yohimbin, yohimbina, yohimbinum, yohimvetol Substance type: aspidosperma alkaloid, indole

alkaloid

Yohimbine was first extracted from the bark of Pausinystalia yohimba and described in the

nineteenth century. It is a typical alkaloid in plants

from the Apocynaceae Family and is related to the

Rauvolfia alkaloids, and it constitutes the primary

alkaloid (1 0/0) in Alstonia angustifolia. It is also

present in some species of Rauvolfia, especially the

African species Rauvolfia macrophylla Stapf

(Timmins and Court 1974).

Yohimbine was once regarded as an MAO

inhibitor, a view that is no longer considered accurate.

Rather, it is simply an a -adrenergic blocker

that consequently stimulates the release of noradrenaline

at the nerve endings. This makes

noradrenaline available in the corpus cavernosum

and results in an erection (Roth et al. 1994, 955*;

Wren 1988,292*).

As a sympathicolytic agent, [yohimbine]

dilates the peripheral blood vessels and

reduces blood pressure. The aphrodisiac effect

is explained through a vasodilatation of the

genital organs and an increased excitability of

the reflexes in the sacral medulla. (Roth et al.

1994,545*)

Yohimbine's aphrodisiac and virility-enhancing

effects, and its therapeutic efficaciousness in

treating impotence, have been demonstrated in a

number of clinical double-blind studies (Buffum

1982; Miller 1968; Sobotka 1969).505

Consequently, yohimbine hydrochloride has

been approved as a specific medicine for the treatment of impotence (sexual neurasthenia). The

recommended dosage is 5 to 10 mg taken three

times daily as a short-term treatment over three to

four weeks. Higher individual dosages (15 to 25

mg) result in psychoactive effects that are somewhat

reminiscent of those of LSD, but with much

less emotional content and an emphasis on

physical phenomena (sexual desire, erotic enjoyment,

and increased sensations of pleasure).

Overdoses can be unpleasant but do not appear to be particularly dangerous (cf. Lewin 1992, 750*):

A chemist had taken an almost 1000-fold

dosage (1.8 g). He became unconscious for a

few hours (during which time a pronounced

priapism was observed) but was able to be

discharged from the hospital within a day.

(Roth et al. 1994,956*)

Commercial Forms and Regulations

The alkaloid is available as yohimbine hydrochloride.

Yohimbine is a prescription medication.
Plants ContainingYohimbine

(from Geschwinde 1996, ·145 f. *; Hofmann

1954;Lewin 1992*; Rompp 1995,5093*; Roth

et al. 1994*; supplemented)

Stock Plant Distribution
Alstonia spp.  
Alstonia angustifolia Old World
Alstonia scholaris Southeast Asia
Aspidosperma South America
quebracho-blanco  
Catharanthus lanceus North America
Corynanthe spp. Africa
Mitragyna stipulosa Africa
(cf.palm wine)  
Pausinystalia yohimba West Africa
Pausirtystalia· macroceras  
Pausinystaliatrillesii  
Rauvolfia spp.  
Rauvolfia macrophylla Africa
Stapf  
Rauvolfia serpentina  
Benth.  
Rauvolfia volkensii Africa
Vincaspp. Africa
(cf. Catharanthus roseus)  

Literature

See also the entries for Alstonia scholaris, Corynanthe

spp., and Pausinystalia yohimba.

Buffum, John. 1982. Pharmacosexology: The effects

of drugs on sexual function-a review. Journal of

Psychoactive Drugs 14 (1-2): 5-44.

Finch, N., and W. I. Taylor. 1962. Oxidative

transformation of indole alkaloids. 1:

Preparation of oxindoles from yohimbine.

Journal of the American Chemical Society

84:3871-77.

Hofmann, Albert. 1954. Die Isolierung weiterer

Alkaloide aus Rauwolfia serpentina Benth.

Helvetica Chimica Acta 37:849-65.

Lambert, G. A., W. J. Lang, E. Friedman, E. Meller,

and S. Gershon. 1978. Pharmacological and

biological properties of isomeric yohimbine

alkaloids. European Journal ofPharmacology

49:39-48.

Leary, Timothy. 1985. Auf der Suche nach dem

wahren Aphrodisiakum und e1ektronischer Sex.

Sphinx Magazin 35.

Miller, W. W. 1968. Afrodex in the treatment of male

impotence: A double-blind cross-over study.

Current Therapeutic Research 10:354-59.

Poisson, J. 1964. Recherches recentes sur les

alcaloYdes du pseudocinchona et du yohimbine.

Ann. Chim. 9:99-121.

Porst, H. 1996. Orale und intracavernose

Pharmakotherapie. TW Urologie Nephrologie 8

(2): 88-94.

Sobotka, J. J. 1969. An evaluation of Afrodex in the

management of male impotency: A double-blind

cross-over study. Current Therapeutic Research

11:87-94.

Timmins, Peter, and William E. Court. 1974.

Alkaloids of Rauwolfia macrophylla.

Phytochemistry 13:281-82.

Weyers, Wolfgang. 1982. Die Empfehlung in der

Selbstmedikation. Heusenstamm: Keppler Verlag.