The most popular alternative medical treatments for erectile dysfunction are derived from the bark of Pausinystalia yohimbe, a tall evergreen tree native to parts of West Africa. It has been used there as an aphrodesiac and treatment for impotence for centuries. The bark of the yohimbe tree contains a cocktail of chemicals, only some of which have been extensively studied.
Mechanism of Action
The alkaloid yohimbine is the plant's primary active constituent and was approved as a pharmaceutical treatment for erectile dysfunction in 1938. Since then, safer and more effective treatments for erectile dysfunction have been developed. Nonetheless, the bark and extracts of the yohimbe tree are still widely recommended by herbalists despite the incidence of moderate to severe side effects. Yohimbine is believed to increase blood supply to the genitals by acting as a calcium channel blocker. Ca2+ blockers divert some of the body's blood supply to the cavernous tissues of the penis, facilitating the male erection. They are also used to lower blood pressure. Yohimbine increases CNS parasympathetic activity and decreases CNS sympathetic nervous system activity, both of which are required for the engorgement of erectile tissue. Despite this, yohimbe has a net hypertensive effect on blood pressure, because it promotes sympathetic nervous system activity throughout the rest of the body by increasing blood levels of noradrenaline.
Other Ingredients
Some of the blood pressure elevating properties of yohimbe may be alleviated by the action of its other chemical constituents. While yohimbine increases blood pressure, corynantheine, dicorynantheine, and ajmaline may diminish its efficacy by their sedative and tranquilizing properties. While yohimbe extracts containing little but yohimbine may be more potent, they have the potential to cause greater hypertension.
Side Effects and Contraindications
Yohimbine directly stimulates the nerves in the sacral region, which may cause increased genital sensitivity and reflex excitability. This in turn may dramatically reduce the time required to reach orgasm in some people. This may also cause the sensation of tingling, shivers or pins-and-needles in the lower back and spine. Its stimulating and blood-pressure elevating properties means that headache, restlessness, anxiety, insomnia, and loss of appetite are also common side effects. If you have been diagnosed with high blood pressure, heart disease, kidney disease, or have a family history of heart attack or stroke, you should not take products containing yohimbe.
Drug Interactions
MayoClinic.com lists yohimbine HCl as a drug useful specifically for the treatment of psychogenic impotence. Unfortunately, yohimbe may interact dangerously with a number of psychiatric medications, including the tricyclic and monoamine oxidase inhibiting antidepressants, as well as the stimulant antidepressant bupropion. According to the Memorial Sloan-Kettering Cancer Center, combining yohimbe with any of these drugs can elicit a potentially fatal hypertensive crisis. MayoClinic.com warns thats methamphetamine and other stimulant drugs are known to produce elevated heart rate and blood pressure when combined with yohimbe. Due to the risk of serious drug interactions, talk to your doctor before using any supplements containing yohimbe.
References
- National Center for Complementary and Alternative Medicine; Yohimbe; July 2010
- Memorial Sloan-Kettering Cancer Center; Yohimbe; March 2011
- National Toxicology Program Study Reports; Yohimbe Bark Extract / Yohimbine; November 1999
- MayoClinic.com; Erectile Dysfunction Herbs: A Natural Treatment for ED?; September 2010
- University of Maryland Medical Center; Impotence (Erectile Dysfunction)
- "Neuroendocrinology"; Yohimbine Increases Cerebrospinal Fluid and Plasma Norepinephrine; Elaine R. Peskind et al.; March 1989
