Drug & supplement interaction

Dimethylhexylamine (dmha) + Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine

Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine brand name: Colrex.

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

Dimethylhexylamine (dmha) has a moderate interaction with Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine. Theoretically, combining DMHA with stimulant drugs might increase the risk of adverse cardiovascular effects.

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

Dimethylhexylamine (dmha) and Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine

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

Moderate

STIMULANT DRUGS

Why this applies to Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine

Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine falls under STIMULANT DRUGS — the group Dimethylhexylamine (dmha) interacts with.

Theoretically, combining DMHA with stimulant drugs might increase the risk of adverse cardiovascular effects.
DMHA is thought to have stimulant 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 piece I want you to focus on with Colrex: this combination product contains phenylephrine, a decongestant that already nudges up your heart rate and blood pressure by acting like a mild stimulant. DMHA is also a stimulant that raises norepinephrine, alertness, heart rate, and blood pressure. Stacking the two together could add up, and theoretically that means a higher chance of feeling jittery, a racing or pounding heartbeat, headache, or a spike in blood pressure.

To be fair, this concern is based on how these ingredients work, not on strong studies, so it's a maybe, not a certainty. Still, DMHA is an ingredient the FDA has flagged as unapproved and risky, and I'd steer clear of it. Please check with your pharmacist or doctor before pairing them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Rasmussen N, Keizers PH. History full circle: 'novel' sympathomimetics in supplements. Drug Test Anal 2016;8(3-4):283-6. PubMed
  2. Monroe RR, Drell HJ. Oral use of stimulants obtained from inhalers. J Am Med Assoc 1947; 135(14):909-15. PubMed
  3. Fellows EJ. The pharmacology of 2-amino-6-methylheptane. J Pharmacol Exp Ther 1947;90(4):351-8. DOI

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

Dimethylhexylamine (dmha) Also Interacts With Other Medications

Dimethylhexylamine (dmha) has 171 moderate known drug interactions in our database — the Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine one above is one of them. If you take anything else, check it against the full list below.

Moderate 171 No known interaction 2,659 (incl. Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine)
Taking anything else?

Check Another of Your Medications Against Dimethylhexylamine (dmha)

Covers the 2,830 medications we’ve checked against Dimethylhexylamine (dmha). Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine

This page covers Dimethylhexylamine (dmha) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine page lists 338 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Asarabacca (major), Beer (major) and Ephedra (major).

By severity: 18 major · 275 moderate · 45 minor.

From our pharmacist’s overview on the Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine page

“Someone taking Colrex is usually fighting a miserable cold, and cold season is also when people reach for herbal sleep aids and energy boosters, which is exactly where this list bites hardest. Colrex combines acetaminophen, chlorpheniramine, codeine, and phenylephrine, and 18 of its 338 supplement interactions rate major, enough to war…”

Reviewed by 2 · Jul 18, 2026

Open the Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine interaction page

One more smart check

Taking Dimethylhexylamine (dmha) as Part of a Dietary Supplement Product? Check It for Interactions

We hold 72 real supplement products containing Dimethylhexylamine (dmha), each one broken down to its full ingredient list — and combination products often carry several ingredients besides Dimethylhexylamine (dmha). Your product may carry other ingredients that interact with Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine too, on top of Dimethylhexylamine (dmha) — 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 Dimethylhexylamine (dmha) and Acetaminophen, Chlorpheniramine, Codeine, 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 Dimethylhexylamine (dmha)
Steady interest

#1,089 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine
Top 10%

#280 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 Dimethylhexylamine (dmha)

What is Dimethylhexylamine (dmha)?

  • Pre-workout energy
  • Fat loss and weight management
  • Athletic performance
  • Appetite suppression
  • Focus and stimulation

DMHA (dimethylhexylamine, also called octodrine) is a synthetic stimulant added to some pre-workout and weight-loss supplements, often falsely labeled as a natural plant extract. It has not been shown to be safe as a dietary supplement, has been flagged by the FDA as an unapproved and potentially dangerous ingredient, and is best avoided. Talk to a pharmacist or doctor before using any product that contains it.

Read the full Dimethylhexylamine (dmha) monograph & all interactions
Keep checking

Other Drugs & Dimethylhexylamine (dmha)

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

0Major
171Moderate
0Minor
2,658No known interaction
171 Moderate 2,658 No interaction
Moderate

171 interactions

Showing 60 of 171 moderate interactions — see all 171 on the Dimethylhexylamine (dmha) page.

No interaction 2,658 drugs checked — show the list

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

Showing the 60 most looked-up of 2,658 medications checked with no known interaction — see the full Dimethylhexylamine (dmha) list.

See the full Dimethylhexylamine (dmha) interactions page
See every supplement checked against Acetaminophen, Chlorpheniramine, Codeine, 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
Dimethylhexylamine (dmha) monograph › Uses, safety, and every drug interaction in one place Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine supplement interactions › Every supplement checked against Acetaminophen, Chlorpheniramine, Codeine, 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 Dimethylhexylamine (dmha) and Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine Together: Common Questions

Can you take Dimethylhexylamine (dmha) with Acetaminophen, Chlorpheniramine, Codeine, 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 Dimethylhexylamine (dmha) and Acetaminophen, Chlorpheniramine, Codeine, 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 Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine and Dimethylhexylamine (dmha)?

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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.