yohimbine
n. a stimulant alkaloid derived from the bark of the African tree Pausinystalia yohimbe and from Rauwolfia serpentina root. It acts as an antagonist at α2-adrenoreceptors (see alpha-adrenergic receptor); at high doses, it is a monoamine oxidase inhibitor and can cause serious adverse effects when taken concomitantly with antidepressants, tyramine-containing foods (e.g., liver, cheeses), or over-the-counter products containing phenylpropanolamine, such as nasal decongestants and diet aids. Yohimbine has achieved a reputation as a sexual enhancer in men, but there is little clinical evidence suggesting its efficacy is greater than placebo. It has also been studied as a potential treatment for erectile dysfunction, with contradictory results regarding its effectiveness. Chemically related to reserpine (see rauwolfia derivative), yohimbine is a sympathomimetic drug and may increase
anxiety or produce panic attacks in susceptible individuals. Side effects may include nervousness, irritability, dizziness, skin flushing, or headache. More serious effects, including renal failure, seizures, and death, have also been reported. Yohimbine should not be taken by people with hypotension (low blood pressure), diabetes, or heart, liver, or kidney disease. It is available as an herbal remedy and also in prescription form (U.S. trade name: Yocon).