General Description
The yohimbe is an evergreen tree native to the jungles of western
Africa. Growing up to 30 meters in height, yohimbe has gray-brown
bark which is fissured and split, and often spotted. The leaves
are long and elliptical in shape. Tinctures and extracts made from
the bark are used medicinally.
Health applications
History and traditional use
Historically, yohimbe bark was used in western Africa for fevers,
coughs, and leprosy. More recently, it has gained popularity as
an aphrodisiac.
Chemical composition
Yohimbe bark contains a mixture of alkaloids, the most active
of which is yohimbine. Yohimbine hydrochloride is sold as a prescription
drug in the U.S. and has been used as a treatment for some types
of male erectile dysfunction (impotence).
Impotence
The popular use of yohimbe as an aphrodisiac has prompted researchers
to investigate the herb's effectiveness in treating erectile dysfunction.
Numerous studies have shown a positive response in impotent men
treated with yohimbine, but the response rate varies from study
to study.1-8 Although yohimbine treatment
was shown to be more effective than placebo, in most studies,
over half of the subjects treated with yohimbine showed no improvement
in sexual function.1-6 Nevertheless, yohimbine
appears to be effective in a significant number of patients with
erectile dysfunction.
Dosage/toxicity
The recommended dosage for yohimbe depends on its yohimbine content.
The alkaloid salt yohimbine hydrochloride is prescribed at 15
mg per day (divided into three doses), and yohimbe extracts providing
an equivalent amount of yohimbine would presumably have a similar
effect. Although studies on yohimbe toxicity are lacking, a number
of adverse side effects have been reported, including anxiety,
elevated heart rate and blood pressure, sleepiness, irritability,
dizziness, headaches, and nausea. Because yohimbine acts as a
weak MAO inhibitor, it should not be taken with mood-altering
drugs or foods rich in tyramine, such as liver, cheese, and red
wines. Yohimbe is not recommended for psychiatric patients, people
with panic disorder, post-traumatic stress disorder, hypertension,
diabetes, renal disorders, or people with a history of gastric
or duodenal ulcers.9-11 |
