Introduction
Yohimbe is an herbal supplement derived from the bark of the Pausinystalia yohimbe tree native to Central Africa. It contains the active alkaloid yohimbine hydrochloride, which has been used traditionally as an aphrodisiac and more recently studied for various medical applications. Unlike FDA-approved pharmaceuticals, yohimbe supplements are marketed as dietary supplements and are not subject to the same regulatory standards.
Mechanism of Action
Yohimbine acts primarily as a selective α₂-adrenergic receptor antagonist. This mechanism:
- Blocks presynaptic α₂-adrenergic receptors, increasing norepinephrine release
- Enhances sympathetic nervous system activity
- Increases parasympathetic cholinergic activity
- May increase nitric oxide synthesis, contributing to vasodilation
- These actions collectively result in increased blood flow to certain tissues and potential effects on sexual function
Indications
FDA-approved indication:- None for herbal yohimbe supplements
- Treatment of erectile dysfunction (not first-line therapy)
- Sexual dysfunction
- Weight loss supplement
- Athletic performance enhancement
- Depression (limited evidence)
Dosage and Administration
Important: Yohimbe supplements vary significantly in potency and standardization Typical supplement dosing:- 5-10 mg of yohimbine hydrochloride equivalent 3 times daily
- Maximum daily dose: 30 mg
- Usually administered orally
- Renal impairment: Use with caution, consider reduced dosing
- Hepatic impairment: Contraindicated
- Elderly: Start with lower doses due to increased sensitivity
- Pediatrics: Not recommended
Pharmacokinetics
Absorption: Rapidly absorbed from GI tract Distribution: Widely distributed throughout body tissues Metabolism: Extensive hepatic metabolism via CYP450 enzymes Elimination: Primarily renal excretion Half-life: Approximately 0.6-2.5 hours Protein binding: Approximately 80%Contraindications
- Known hypersensitivity to yohimbine or related compounds
- Renal disease
- Hepatic impairment
- Cardiovascular disease including hypertension, angina, heart failure
- Psychiatric disorders including anxiety, panic disorders
- Pregnancy and breastfeeding
- Concurrent use of antidepressants (especially MAOIs)
- History of prostate cancer
Warnings and Precautions
- Black Box Warning: None, but significant safety concerns exist
- May cause severe hypertension and tachycardia
- Risk of serotonin syndrome when combined with serotonergic drugs
- Potential for anxiety, panic attacks, and mood alterations
- Not recommended for use without medical supervision
- Quality control issues with dietary supplements may lead to inconsistent dosing
Drug Interactions
Major interactions:- MAO inhibitors: Risk of hypertensive crisis
- SSRIs/SNRIs: Increased risk of serotonin syndrome
- Antihypertensives: May antagonize effects
- Sympathomimetics: Additive cardiovascular effects
- Tricyclic antidepressants: Increased cardiovascular effects
- CNS depressants: Altered effects
- Antipsychotics
- Diabetes medications
- Other herbal supplements with cardiovascular effects
Adverse Effects
Common (≥1%):- Anxiety, nervousness
- Dizziness
- Headache
- Nausea
- Increased blood pressure
- Tachycardia
- Sweating
- Severe hypertension
- Cardiac arrhythmias
- Myocardial infarction
- Seizures
- Renal failure
- Psychiatric symptoms (panic attacks, hallucinations)
- Serotonin syndrome
Monitoring Parameters
- Blood pressure (baseline and regularly during use)
- Heart rate and rhythm
- Renal function tests
- Liver function tests
- Mental status assessment
- Symptoms of anxiety or panic
- Sexual function assessment (if used for ED)
Patient Education
- Yohimbe is not FDA-approved as a dietary supplement
- Quality and potency may vary significantly between products
- Report any chest pain, palpitations, or severe anxiety immediately
- Avoid use if you have any cardiovascular conditions
- Inform all healthcare providers about yohimbe use
- Do not combine with other stimulants or antidepressants
- Discontinue use and seek medical attention if adverse effects occur
- Not recommended for long-term use without medical supervision
References
1. National Center for Complementary and Integrative Health. Yohimbe. Updated 2020. 2. De Smet PA. Herbal remedies. N Engl J Med. 2002;347(25):2046-2056. 3. Ernst E, Pittler MH. Yohimbine for erectile dysfunction: a systematic review and meta-analysis of randomized clinical trials. J Urol. 1998;159(2):433-436. 4. Goldberg MR, Robertson D. Yohimbine: a pharmacological probe for study of the alpha 2-adrenoreceptor. Pharmacol Rev. 1983;35(3):143-180. 5. Natural Medicines Database. Yohimbe. Updated 2023. 6. FDA. Dietary Supplements. Accessed 2023. 7. Kearney T, Tu N. Yohimbine: a clinical review. Pharmacol Ther. 1991;49(1):1-34.
Note: This monograph is for educational purposes only. Yohimbe supplements are not recommended for use without medical supervision due to significant safety concerns and variable product quality.