Drug Interaction Report

Hydralazine and Yohimbine: Interaction Details

A pharmacist-reviewed analysis of the Hydralazine 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

Hydralazine

Apresoline® Dralzine®
+

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.

Of 12 documented Hydralazine interactions, 5 are rated moderate — including this one.
Onset
rapid
Evidence
theoretical
Severity
Moderate

What happens

Reduced hydrALAZINE effectiveness

Interaction Deep Dive

Theoretically, yohimbine may directly counteract the hypotensive effect of hydrALAZINE, resulting in inadequate blood pressure control in hypertensive patients. Yohimbine increased blood pressure in hypertensive and normotensive patients in several studies12345. 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 4.

Why it happens (mechanism)

Increased norepinephrine release by yohimbine

Common questions

Can I take Hydralazine and Yohimbine together?

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

How serious is the Hydralazine 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 "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

From our Q&A

Real reader questions about these medications, each personally answered by our pharmacist:

Questions for your pharmacist

  • Does my dose of Hydralazine 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 (5)

  1. 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. DOI
  2. 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.
  3. 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
  4. 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. DOI
  5. 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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Hydralazine

Keep reading about Hydralazine

All Hydralazine interactions (12) Hydralazine drug information
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Yohimbine

Keep reading about Yohimbine

All Yohimbine interactions (47)
Also serious with: Sertraline Abiraterone
Beyond drug–drug

These medications also interact with supplements

Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

Hydralazine + Activated Charcoal American Hellebore American Mistletoe Tyramine Adrafinil Agmatine Algal Oil Andrographis + 128 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.