Drug & supplement interaction

Yohimbe + Dextromethorphan HBr, Phenylephrine HCl

Dextromethorphan HBr, Phenylephrine HCl brand name: Vicks Formula 44D Cough & Head Congestion Relief.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Dextromethorphan HBr, Phenylephrine HCl falls into 3 drug categories that Yohimbe can interact with; the most serious is rated moderate. Theoretically, yohimbe might increase the levels and adverse effects of CYP2D6 substrates.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Yohimbe and Dextromethorphan HBr, Phenylephrine HCl

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Yohimbe interacts with whole categories of medication. Dextromethorphan HBr, Phenylephrine HCl falls into 3 of those categories, so it can interact with Yohimbe in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

1 of 3

Why this applies to Dextromethorphan HBr, Phenylephrine HCl

Dextromethorphan HBr, Phenylephrine HCl falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group Yohimbe interacts with.

Theoretically, yohimbe might increase the levels and adverse effects of CYP2D6 substrates.
In vitro research suggests that yohimbine, a constituent of yohimbe bark, inhibits CYP2D6 enzyme activity.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the gist with this cough and congestion combo. Your body uses an enzyme called CYP2D6 to break down dextromethorphan, the cough suppressant in Vicks Formula 44D. Lab studies hint that yohimbine (from yohimbe) may slow that enzyme down. If it does, dextromethorphan could build up a bit, which might mean more drowsiness, dizziness, or feeling foggy than usual.

I'll be honest though, this is only seen in test-tube research, so it's theoretical and not proven in real people. The bigger worry is actually the overlap with phenylephrine, since both yohimbe and phenylephrine can raise blood pressure and speed up your heart. Before pairing them, check with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. VandenBrink, B. M., Foti, R. S., Rock, D. A., Wienkers, L. C., and Wahlstrom, J. L. Prediction of CYP2D6 drug interactions from in vitro data: evidence for substrate-dependent inhibition. Drug Metab Dispos. 2012;40(1):47-53. PubMed
Moderate

STIMULANT DRUGS

2 of 3

Dextromethorphan HBr, Phenylephrine HCl also falls under STIMULANT DRUGS.

Theoretically, taking yohimbe with stimulant drugs can have additive effects.
Yohimbine, a constituent of yohimbe, has sympathomimetic effects and increases blood pressure in a dose-dependent manner. Theoretically, taking yohimbe with stimulant drugs can have additive stimulant and hypertensive effects.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the thing to watch with this combo: the phenylephrine in your Vicks 44D is a decongestant that works by tightening blood vessels, which can nudge your blood pressure and heart rate up. Yohimbe has its own stimulant-like (sympathomimetic) action and can also raise blood pressure. Stack the two together and those effects may add up, so you could notice a racing or pounding heart, jitteriness, headache, or higher blood pressure.

I'll be honest, this is a theoretical concern based on how both work, not something proven in studies, so I don't want to alarm you. Still, if you already deal with high blood pressure or heart issues, it's worth a quick chat with your pharmacist or doctor before pairing them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.
  2. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  3. Bharucha AE, Skaar T, Andrews CN, et al Relationship of cytochrome P450 pharmacogenetics to the effects of yohimbine on gastrointestinal transit and catecholamines in healthy subjects. Neurogastroenterol Motil. 2008;20(8):891-9. PubMed
Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

3 of 3

Dextromethorphan HBr, Phenylephrine HCl also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, yohimbe might decrease the levels and clinical effects of CYP3A4 substrates.
In vitro research shows that yohimbe extract induces CYP3A4 enzymes.
Severity Minor Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the gist for this cough and congestion combo. The dextromethorphan part of Vicks Formula 44D is partly handled by a liver enzyme called CYP3A4. Lab studies suggest yohimbe may speed that enzyme up a bit, which could in theory clear dextromethorphan a little faster and make it slightly less effective at quieting your cough. This is only test-tube evidence, rated minor, so I wouldn't lose sleep over it.

Honestly, my bigger concern is overlap, not metabolism. Yohimbe can raise blood pressure and speed up the heart, and the phenylephrine here is a decongestant that does the same thing. Stacking them could leave you jittery, with a pounding or racing heart. If you take blood pressure or heart medicine, please check with your pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Haron MH, Dale O, Martin K, et al. Evaluation of the Herb-Drug Interaction Potential of Commonly Used Botanicals on the US Market with Regard to PXR- and AhR-Mediated Influences on CYP3A4 and CYP1A2. J Diet Suppl 2022. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Yohimbe Also Interacts With Other Medications

Yohimbe has 9 major, 679 moderate, 436 minor known drug interactions in our database — the Dextromethorphan HBr, Phenylephrine HCl one above is among them. If you take anything else, check it against the full list below.

Major 9 Moderate 679 Minor 436 No known interaction 1,706 (incl. Dextromethorphan HBr, Phenylephrine HCl)
Taking anything else?

Check Another of Your Medications Against Yohimbe

Covers the 2,830 medications we’ve checked against Yohimbe. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Dextromethorphan HBr, Phenylephrine HCl

This page covers Yohimbe only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Dextromethorphan HBr, Phenylephrine HCl page lists 197 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Ephedra (major), Grapefruit (major), Lithium (major) and Peyote (major).

By severity: 8 major · 148 moderate · 41 minor.

From our pharmacist’s overview on the Dextromethorphan HBr, Phenylephrine HCl page

“The supplement interactions with Dextromethorphan HBr and Phenylephrine HCl (Vicks Formula 44D) deserve real respect, and the small cluster of major-rated ones should be understood before you reach for the bottle. Phenylephrine is a stimulant-type decongestant, so anything with caffeine (coffee, tea, cola nut) or ephedrine-like herbs s…”

Reviewed by 2 · Jul 18, 2026

Open the Dextromethorphan HBr, Phenylephrine HCl interaction page

One more smart check

Taking Yohimbe as Part of a Dietary Supplement Product? Check It for Interactions

We hold 1,054 real supplement products containing Yohimbe, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Yohimbe. Your product may carry other ingredients that interact with Dextromethorphan HBr, Phenylephrine HCl too, on top of Yohimbe — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Yohimbe and Dextromethorphan HBr, Phenylephrine HCl Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Yohimbe
Top 25%

#163 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Dextromethorphan HBr, Phenylephrine HCl
Steady interest

#2,556 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Yohimbe

What is Yohimbe?

Yohimbe
  • Erectile dysfunction
  • Low sex drive
  • Sexual performance
  • Weight loss
  • Athletic performance

Yohimbe is a West African tree bark that contains yohimbine, a compound mainly promoted for erectile dysfunction and as an aphrodisiac. A prescription form of yohimbine has some evidence for erectile dysfunction, but over-the-counter yohimbe supplements vary widely in content and can cause serious side effects like high blood pressure and fast heart rate. Because of these safety concerns, talk to your pharmacist or doctor before using it.

Read the full Yohimbe monograph & all interactions
Keep checking

Other Drugs & Yohimbe

Browse every other medication we’ve checked against Yohimbe — both the ones with a known interaction and the ones without. Select any drug for the full detail.

9Major
679Moderate
436Minor
1,705No known interaction
9 Major 679 Moderate 436 Minor 1,705 No interaction
Major

9 interactions

Moderate

679 interactions

Showing 60 of 679 moderate interactions — see all 679 on the Yohimbe page.

Minor

436 interactions

Showing 60 of 436 minor interactions — see all 436 on the Yohimbe page.

No interaction 1,705 drugs checked — show the list

We also checked Yohimbe against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 1,705 medications checked with no known interaction — see the full Yohimbe list.

See the full Yohimbe interactions page
See every supplement checked against Dextromethorphan HBr, Phenylephrine HCl, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Yohimbe monograph › Uses, safety, and every drug interaction in one place Dextromethorphan HBr, Phenylephrine HCl supplement interactions › Every supplement checked against Dextromethorphan HBr, Phenylephrine HCl, ranked by severity Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Yohimbe and Dextromethorphan HBr, Phenylephrine HCl Together: Common Questions

Can you take Yohimbe with Dextromethorphan HBr, Phenylephrine HCl?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 3 interactions listed for Yohimbe and Dextromethorphan HBr, Phenylephrine HCl?
Dextromethorphan HBr, Phenylephrine HCl belongs to more than one drug category, and Yohimbe interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Yohimbe and Dextromethorphan HBr, Phenylephrine HCl interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.