Drug Interaction Report

Guanabenz and Yohimbine: Interaction Details

A pharmacist-reviewed analysis of the Guanabenz and Yohimbine interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Guanabenz

Wytensin®
+

Yohimbine

No brand names on record
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Moderate
Can be significant — usually manageable with monitoring.
How we grade severity & evidence

Severity levels

  • Contraindicated: These should generally not be used together.
  • Major: Potentially serious — often needs a change or close monitoring.
  • Moderate: Can be significant — usually manageable with monitoring.
  • Minor: Usually limited clinical impact.

Evidence grades

  • Established: Well documented — supported by controlled studies or strong clinical data.
  • Probable: Good supporting evidence, though not definitively proven.
  • Suspected: Some evidence suggests this interaction, but it is not well established.
  • Possible: Limited or conflicting evidence; the interaction may occur.
  • Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.

Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.

Onset
rapid
Evidence
probable
Severity
Moderate

What happens

Reduced guanabenz effectiveness

Interaction Deep Dive

Theoretically, yohimbine may counteract the antihypertensive effect of guanabenz. Opposing mechanisms of action resulted in opposite effects on blood pressure by yohimbine and clonidine, a central alpha-adrenergic agonist like guanabenz1. Yohimbine increased blood pressure in hypertensive and normotensive patients in several studies 23456. Yohimbine is believed to increase norepinephrine release by at least one of three mechanisms: direct stimulation of sympathetic outflow from the brain; blockade of inhibitory alpha2-adrenergic receptors on sympathetic nerve endings; blockade of alpha2-adrenergic receptors on vascular smooth muscle with vasodilation eliciting reflexive increases in sympathetic outflow 5.

Why it happens (mechanism)

Increased norepinephrine release by guanabenz

Literature reports

1 report — tap to read

a) In 10 healthy male subjects, yohimbine 30 mg orally significantly increased blood pressure and plasma free 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) (p less than 0.001), which was attenuated by clonidine 5 microgram/kilogram (mcg/kg). Yohimbine increased standing systolic blood pressure from 115 +/- 10 mmHg at baseline to 132 +/- 12 mmHg (p less than 0.001) at 60 minutes versus the combination of yohimbine with clonidine which at baseline was 119 +/- 10 mmHg and decreased to 110 +/- 13 mmHg (p less than 0.01) 1.

Common questions

Can I take Guanabenz and Yohimbine together?

Reduced guanabenz effectiveness Always confirm with your pharmacist or prescriber before making any change.

How serious is the Guanabenz and Yohimbine interaction?

It is rated moderate. Can be significant — usually manageable with monitoring.

How quickly could this interaction happen?

The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.

How strong is the evidence for this interaction?

The evidence is graded "probable". Good supporting evidence, though not definitively proven.

Questions for your pharmacist

  • Does my dose of Guanabenz or Yohimbine need adjusting while I take them together?
  • What symptoms should prompt me to call you or my prescriber right away?
  • Does the timing of my doses matter for this combination?
  • Is there anything you'd monitor while I'm on both?

References (6)

  1. Charney DS, Heninger GR, & Redmond DE: Yohimbine induced anxiety and increased noradrenergic function in humans: effects of diazepam and clonidine. Life Sci 1983; 33:19-29. PubMed
  2. Musso NR, Vergassaol C, Pjende A, et al: Yohimbine effects on blood pressure and plasma catecholamines in human hypertension. Am J Hypertens 1995; 8(6):565-571. PubMed
  3. Grossman E, Rosenthal T, Peleg E, et al: Oral yohimbine increased blood pressure and sympathetic nervous outflow in hypertensive patients. J Cardiovasc Pharmacol 1993; 22(1):22-26.
  4. Damase-Michel C, Tran MA, Llau ME, et al: The effect of yohimbine on sympathetic responsiveness in essential hypertension. Eur J Clin Pharmacol 1993; 44(2):199-201. PubMed
  5. Goldstein DS, Grossman E, Listwak S, et al: Sympathetic reactivity during a yohimbine challenge test in essential hypertension. Hypertension 1991; 18(Suppl 5):III40-48. PubMed
  6. Murburg MM, Villacres EC, Ko GN, et al: Effects of yohimbine on human sympathetic nervous system function. J Clin Endocrinol Metab 1991; 73(4):861-865. PubMed
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Guanabenz

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Yohimbine

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