Drug & supplement interaction

Rauwolscine + Dextromethorphan HBr, Guaifenesin

Dextromethorphan HBr, Guaifenesin brand names: Vicks Formula 44E Cough & Chest Congestion Relief, Pediatric Vicks Formula 44e Cough & Chest Congesti.

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

Rauwolscine has a moderate interaction with Dextromethorphan HBr, Guaifenesin. Theoretically, rauwolscine might increase levels of drugs metabolized by CYP2D6.

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

Rauwolscine and Dextromethorphan HBr, Guaifenesin

Here is the interaction we found between these two, with the evidence behind it.

Moderate

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

Why this applies to Dextromethorphan HBr, Guaifenesin

Dextromethorphan HBr, Guaifenesin falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group Rauwolscine interacts with.

Theoretically, rauwolscine might increase levels of drugs metabolized by CYP2D6.
Rauwolscine is structurally related to yohimbine. In vitro research shows that yohimbine 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 for your cough syrup. The dextromethorphan part is cleared from your body mainly by a liver enzyme called CYP2D6. Rauwolscine is a cousin of yohimbine, and lab tests suggest yohimbine can slow that enzyme down. If that holds true, your body might clear dextromethorphan a little slower, letting it build up. That could mean more drowsiness, dizziness, lightheadedness, or a foggy, jittery feeling. The guaifenesin half isn't really affected here.

I'll be honest, this is a theoretical concern based on lab data, not real patient reports, so I wouldn't lose sleep over it. Still, since rauwolscine itself can rev up heart rate and anxiety, it's worth a quick chat with your pharmacist before combining them.

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

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

Rauwolscine Also Interacts With Other Medications

Rauwolscine has 676 moderate known drug interactions in our database — the Dextromethorphan HBr, Guaifenesin one above is one of them. If you take anything else, check it against the full list below.

Moderate 676 No known interaction 2,154 (incl. Dextromethorphan HBr, Guaifenesin)
Taking anything else?

Check Another of Your Medications Against Rauwolscine

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

Everything else you take

See Every Supplement That Interacts With Dextromethorphan HBr, Guaifenesin

This page covers Rauwolscine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Dextromethorphan HBr, Guaifenesin page lists 171 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), Lithium (major), St. John's Wort (major) and 1,3-dmaa (moderate).

By severity: 4 major · 125 moderate · 42 minor.

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

“A bad cough tends to hit when supplements are already on the counter, and anyone reaching for Vicks Formula 44E (dextromethorphan HBr and guaifenesin) should treat this list with real care, since 4 of its 171 entries carry a major rating. Two themes dominate.”

Reviewed by 2 · Jul 18, 2026

Open the Dextromethorphan HBr, Guaifenesin interaction page

One more smart check

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

We hold 196 real supplement products containing Rauwolscine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Rauwolscine. Your product may carry other ingredients that interact with Dextromethorphan HBr, Guaifenesin too, on top of Rauwolscine — 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 Rauwolscine and Dextromethorphan HBr, Guaifenesin 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 Rauwolscine
Top 25%

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

29 days ago today
Medication Dextromethorphan HBr, Guaifenesin
Top 25%

#565 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 Rauwolscine

What is Rauwolscine?

  • Fat loss and weight management
  • Bodybuilding and physique support
  • Energy and stimulant effects
  • Athletic performance
  • Libido support

Rauwolscine (alpha-yohimbine) is a stimulant alkaloid closely related to yohimbine that is marketed mainly in fat-burning and pre-workout supplements. Human evidence for its benefits is very limited, and it can raise heart rate and blood pressure and cause anxiety, so it should be used with caution and is not recommended for people with heart conditions, anxiety, or during pregnancy or breastfeeding.

Read the full Rauwolscine monograph & all interactions
Keep checking

Other Drugs & Rauwolscine

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

0Major
676Moderate
0Minor
2,153No known interaction
676 Moderate 2,153 No interaction
Moderate

676 interactions

Showing 60 of 676 moderate interactions — see all 676 on the Rauwolscine page.

No interaction 2,153 drugs checked — show the list

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

Showing the 60 most looked-up of 2,153 medications checked with no known interaction — see the full Rauwolscine list.

See the full Rauwolscine interactions page
See every supplement checked against Dextromethorphan HBr, Guaifenesin, 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
Rauwolscine monograph › Uses, safety, and every drug interaction in one place Dextromethorphan HBr, Guaifenesin supplement interactions › Every supplement checked against Dextromethorphan HBr, Guaifenesin, 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 Rauwolscine and Dextromethorphan HBr, Guaifenesin Together: Common Questions

Can you take Rauwolscine with Dextromethorphan HBr, Guaifenesin?
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.
How serious is the Rauwolscine and Dextromethorphan HBr, Guaifenesin 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

Still Have a Question About Dextromethorphan HBr, Guaifenesin and Rauwolscine?

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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.