Yohimbine: a clinical review.
Although yohimbine (YOH) has been available for the treatment of male erectile dysfunction (ED) for longer than Viagra, there is a perception that little is known about the clinical performance of the drug. This review attempts, by comprehensive analysis of the literature, to cover the clinical, pharmacological, and therapeutic profiles of YOH, relevant to its potential utility in the management of patients with ED. Relatively few well-designed studies have been completed. From these, however, it can be concluded that YOH as monotherapy possesses only modest efficacy in ED patients. In acute and chronic (long-term) studies, YOH has been found to be relatively free of side effects over the dose range predicted to be effective in ED. At much higher doses, the most frequently observed effects, consistent with the primary pharmacological action of the drug, are elevation of blood pressure, a slight anxiogenic action, and increased frequency of urination. These side effects are all easily reversible on termination of YOH therapy. There is increasing evidence that the erectogenic action of YOH can be augmented by concomitant administration of agents that augment the release and/or action of nitric oxide in the corpus cavernosum. YOH has yet to be studied in female sexual dysfunction. Overall, the benefit risk profile of YOH would indicate that it has potential, more probably as part of a combination strategy, e.g., with a drug that enhances the nitric oxide pathway, in the treatment of ED.