Drug & supplement interaction

Terminalia + Brompheniramine, Dextromethorphan, Phenylephrine

Brompheniramine, Dextromethorphan, Phenylephrine brand name: Dimetapp DM.

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

Terminalia has a moderate interaction with Brompheniramine, Dextromethorphan, Phenylephrine. Theoretically, use of Terminalia arjuna may increase the levels and clinical effects of CYP2D6 substrates.

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

Terminalia and Brompheniramine, Dextromethorphan, Phenylephrine

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

Moderate

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

Why this applies to Brompheniramine, Dextromethorphan, Phenylephrine

Brompheniramine, Dextromethorphan, Phenylephrine falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group Terminalia interacts with.

Theoretically, use of Terminalia arjuna may increase the levels and clinical effects of CYP2D6 substrates.
In vitro research shows that Terminalia arjuna extract inhibits CYP2D6 enzymes and reduces CYP2D6 substrate metabolism.
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 situation with Dimetapp DM and Terminalia. One of the ingredients, dextromethorphan (the cough suppressant), is cleared by a liver enzyme called CYP2D6. Lab studies suggest Terminalia arjuna may slow that enzyme down. If that happens in the body, dextromethorphan could build up a bit, which might mean more drowsiness, dizziness, or feeling foggy. The brompheniramine (antihistamine) can add to that sleepiness too.

I want to be honest though: this is based only on test-tube research, not real people, so it's theoretical and likely mild. Still, if you take Terminalia regularly and notice extra grogginess, check in with your pharmacist or doctor before changing anything.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Varghese A, Savai J, Pandita N, Gaud RS. In vitro modulatory effects of Terminalia arjuna, arjunic acid, arjunetin, and arjungenin on CYP3A4, CYP2D6, and CYP2C9 enzyme activity in human liver microsomes. Toxicology Reports. 2015(2):806-16. 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

Terminalia Also Interacts With Other Medications

Terminalia has 932 moderate known drug interactions in our database — the Brompheniramine, Dextromethorphan, Phenylephrine one above is one of them. If you take anything else, check it against the full list below.

Moderate 932 No known interaction 1,898 (incl. Brompheniramine, Dextromethorphan, Phenylephrine)
Taking anything else?

Check Another of Your Medications Against Terminalia

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

Everything else you take

See Every Supplement That Interacts With Brompheniramine, Dextromethorphan, Phenylephrine

This page covers Terminalia 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

One more smart check

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

We hold 306 real supplement products containing Terminalia, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Terminalia. Your product may carry other ingredients that interact with Brompheniramine, Dextromethorphan, Phenylephrine too, on top of Terminalia — 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 Terminalia 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 Terminalia
Top 25%

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

29 days ago today
Medication Brompheniramine, Dextromethorphan, Phenylephrine
Top 25%

#476 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 Terminalia

What is Terminalia?

Terminalia
  • Heart health and circulation
  • Digestive problems (constipation, diarrhea)
  • Cholesterol support
  • Antioxidant and anti-inflammatory support
  • Immune support

Terminalia is a group of traditional Ayurvedic tree species (most notably Terminalia arjuna) used for heart, digestive, and general wellness purposes. Some small studies suggest possible benefits for heart and cholesterol health, but the evidence is limited and not strong enough to recommend it as a treatment. Talk to your pharmacist or doctor before using it, especially if you have a heart condition.

Read the full Terminalia monograph & all interactions
Keep checking

Other Drugs & Terminalia

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

0Major
932Moderate
0Minor
1,897No known interaction
932 Moderate 1,897 No interaction
Moderate

932 interactions

Showing 60 of 932 moderate interactions — see all 932 on the Terminalia page.

No interaction 1,897 drugs checked — show the list

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

Showing the 60 most looked-up of 1,897 medications checked with no known interaction — see the full Terminalia list.

See the full Terminalia 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
Terminalia 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 Terminalia and Brompheniramine, Dextromethorphan, Phenylephrine Together: Common Questions

Can you take Terminalia 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.
How serious is the Terminalia 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

Still Have a Question About Brompheniramine, Dextromethorphan, Phenylephrine and Terminalia?

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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.