Drug & supplement interaction

1,3-dmba + Brompheniramine, Dextromethorphan, Phenylephrine

Brompheniramine, Dextromethorphan, Phenylephrine brand name: Dimetapp DM.

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

Brompheniramine, Dextromethorphan, Phenylephrine falls into 2 drug categories that 1,3-dmba can interact with; the most serious is rated moderate. Theoretically, combining 1,3-DMBA with other stimulant drugs might increase the risk of cardiovascular toxicity.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

1,3-dmba and Brompheniramine, Dextromethorphan, Phenylephrine

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

1,3-dmba interacts with whole categories of medication. Brompheniramine, Dextromethorphan, Phenylephrine falls into 2 of those categories, so it can interact with 1,3-dmba in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

STIMULANT DRUGS

1 of 2

Why this applies to Brompheniramine, Dextromethorphan, Phenylephrine

Brompheniramine, Dextromethorphan, Phenylephrine falls under STIMULANT DRUGS — the group 1,3-dmba interacts with.

Theoretically, combining 1,3-DMBA with other stimulant drugs might increase the risk of cardiovascular toxicity.
Animal research shows that 1,3-DMBA has stimulant effects, such as increasing blood pressure and heart rate.
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 for with Dimetapp DM: it contains phenylephrine, a decongestant that already nudges up your blood pressure and heart rate by tightening blood vessels. 1,3-DMBA is a stimulant believed to do the very same thing. Stacking two vessel-tightening stimulants together can add up, and in theory that raises the chance of cardiovascular strain like a racing or pounding heart, jitteriness, headache, or higher blood pressure.

To be honest, this is a theoretical concern based mostly on animal data, so I don't want to overstate it. But 1,3-DMBA isn't a safe or legal supplement ingredient to begin with, so I'd steer clear of it entirely. Please check with your pharmacist or doctor before mixing the two.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. SWANSON EE, CHEN KK. Comparison of pressor action of alicyclic derivatives of aliphatic amines. J Pharmacol Exp Ther. 1948 Aug;93(4):423-9.
Minor

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

2 of 2

Brompheniramine, Dextromethorphan, Phenylephrine also falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES.

Theoretically, 1,3-DMBA might modestly increase the levels of CYP2D6 substrates.
In vitro research shows that 1,3-DMBA weakly inhibits CYP2D6 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 short version: in Dimetapp DM, the cough-calming ingredient dextromethorphan is cleared by a liver enzyme called CYP2D6. Lab-dish studies suggest 1,3-DMBA may weakly block that enzyme. In theory, that could let dextromethorphan build up a bit, which might mean more drowsiness, dizziness, or that 'foggy' feeling. This is only a minor, theoretical concern based on test-tube data, not real people, so I wouldn't lose sleep over the drug side of it.

My bigger worry is 1,3-DMBA itself. It's an unapproved, banned stimulant, and this product already contains phenylephrine, which also raises blood pressure. Stacking them could push your heart rate and blood pressure up. I'd steer clear of 1,3-DMBA and check with your pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Liu Y, Santillo MF. Cytochrome P450 2D6 and 3A4 enzyme inhibition by amine stimulants in dietary supplements. Drug Test Anal. 2016;8(3-4):307-10. 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

1,3-dmba Also Interacts With Other Medications

1,3-dmba has 171 moderate, 149 minor known drug interactions in our database — the Brompheniramine, Dextromethorphan, Phenylephrine one above is among them. If you take anything else, check it against the full list below.

Moderate 171 Minor 149 No known interaction 2,510 (incl. Brompheniramine, Dextromethorphan, Phenylephrine)
Taking anything else?

Check Another of Your Medications Against 1,3-dmba

Covers the 2,830 medications we’ve checked against 1,3-dmba. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Brompheniramine, Dextromethorphan, Phenylephrine

This page covers 1,3-dmba only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Brompheniramine, Dextromethorphan, Phenylephrine page lists 149 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: 7 major · 120 moderate · 22 minor.

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

“Dimetapp DM, the cold medicine combining brompheniramine, dextromethorphan, and phenylephrine, earns more caution than its over-the-counter status suggests. Seven of the 149 supplement ingredients on this page carry a major rating, and most of those stack stimulant effects on top of phenylephrine, pushing blood pressure and heart strai…”

Reviewed by 2 · Jul 18, 2026

Open the Brompheniramine, Dextromethorphan, Phenylephrine interaction page

How much people look this up

Where 1,3-dmba and Brompheniramine, Dextromethorphan, Phenylephrine 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 1,3-dmba
Steady interest

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

29 days ago today
Medication Brompheniramine, Dextromethorphan, Phenylephrine
Steady interest

#2,089 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 1,3-dmba

What is 1,3-dmba?

  • Athletic and workout performance
  • Energy and stimulation
  • Weight loss and fat burning
  • Appetite suppression
  • Focus and concentration

1,3-DMBA is a synthetic stimulant chemically similar to the banned stimulant DMAA, and it is not a proven or safe dietary ingredient. The U.S. FDA considers supplements containing it adulterated, and it is banned in sports. Because of serious heart and stroke risks, it is best to avoid products that contain it.

Read the full 1,3-dmba monograph & all interactions
Keep checking

Other Drugs & 1,3-dmba

Browse every other medication we’ve checked against 1,3-dmba — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
171Moderate
149Minor
2,509No known interaction
171 Moderate 149 Minor 2,509 No interaction
Moderate

171 interactions

Showing 60 of 171 moderate interactions — see all 171 on the 1,3-dmba page.

Minor

149 interactions

Showing 60 of 149 minor interactions — see all 149 on the 1,3-dmba page.

No interaction 2,509 drugs checked — show the list

We also checked 1,3-dmba against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,509 medications checked with no known interaction — see the full 1,3-dmba list.

See the full 1,3-dmba interactions page
See every supplement checked against Brompheniramine, Dextromethorphan, Phenylephrine, 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
1,3-dmba monograph › Uses, safety, and every drug interaction in one place Brompheniramine, Dextromethorphan, Phenylephrine supplement interactions › Every supplement checked against Brompheniramine, Dextromethorphan, Phenylephrine, 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 1,3-dmba and Brompheniramine, Dextromethorphan, Phenylephrine Together: Common Questions

Can you take 1,3-dmba with Brompheniramine, Dextromethorphan, Phenylephrine?
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 2 interactions listed for 1,3-dmba and Brompheniramine, Dextromethorphan, Phenylephrine?
Brompheniramine, Dextromethorphan, Phenylephrine belongs to more than one drug category, and 1,3-dmba 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 1,3-dmba and Brompheniramine, Dextromethorphan, Phenylephrine 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.