Corynanthe yohimbe

Yohimbe bark contains yohimbine, a selective alpha-2 adrenoceptor antagonist. By blocking alpha-2 receptors, yohimbine inhibits norepinephrine's vasoconstrictive effects, promoting vasodilation in penile blood vessels. This mechanism increases blood flow to erectile tissue. Yohimbine also acts centrally on the nervous system, though its primary effect is peripheral. Evidence Level: C (limited-quality clinical evidence). Related alkaloids like corynanthine contribute additional adrenoceptor activity.

Yohimbe has significant drug interactions. It is contraindicated with MAOIs (monoamine oxidase inhibitors), as this combination can trigger hypertensive crisis. Yohimbe should not be combined with blood pressure medications, tricyclic antidepressants, stimulants, or other sympathomimetic agents due to additive cardiovascular effects. Patients taking clonidine, beta-blockers, or nitrates should avoid yohimbe. Always consult a healthcare provider before combining yohimbe with prescription medications.

Clinical studies have used yohimbine hydrochloride at 5-20mg daily, typically divided into 2-3 doses. For standardized yohimbe bark extract, follow manufacturer guidelines to achieve equivalent yohimbine content. Start with the lowest effective dose to assess tolerance. Evidence Level: C. Raw bark preparations vary significantly in alkaloid content, making standardized extracts preferable for consistent dosing. Do not exceed recommended doses without medical supervision.

Yohimbe is contraindicated during pregnancy and breastfeeding. Yohimbine can stimulate uterine contractions, potentially causing miscarriage or premature labor. The alkaloid crosses the placenta and may affect fetal circulation and development. Yohimbine's effects on maternal blood pressure and heart rate pose additional risks. No safe exposure level has been established. Women who are pregnant, planning pregnancy, or breastfeeding should avoid yohimbe entirely.

Common side effects include tachycardia, elevated blood pressure, anxiety, nervousness, insomnia, and gastrointestinal upset. Users may experience headaches, dizziness, flushing, and sweating. More serious adverse effects include heart palpitations, panic attacks, and liver toxicity with prolonged use. Individuals with hypertension, anxiety disorders, heart disease, or liver/kidney conditions should avoid yohimbe. Discontinue use immediately if severe cardiovascular or psychiatric symptoms occur.