Drug & supplement interaction

1,3-dmaa + Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine

Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine brand name: Theracaps.

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

Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine falls into 2 drug categories that 1,3-dmaa can interact with; the most serious is rated moderate. 1,3-DMAA strongly inhibits cytochrome P450 2D6 (CYP2D6) enzymes in vitro.

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

1,3-dmaa and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine

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

Why Are There 2 Interactions?

1,3-dmaa interacts with whole categories of medication. Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine falls into 2 of those categories, so it can interact with 1,3-dmaa in 2 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 2

Why this applies to Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine

Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group 1,3-dmaa interacts with.

1,3-DMAA strongly inhibits cytochrome P450 2D6 (CYP2D6) enzymes in vitro. Theoretically, 1,3-DMAA can increase levels of CYP2D6 substrates. Some of drugs that are CYP2D6 substrates include amitriptyline (Elavil), clozapine (Clozaril), codeine, desipramine (Norpramin), donepezil (Aricept), fentanyl (Duragesic), flecainide (Tambocor), fluoxetine (Prozac), meperidine (Demerol), methadone (Dolophine), metoprolol (Lopressor, Toprol XL), olanzapine (Zyprexa), ondansetron (Zofran), tramadol (Ultram), trazodone (Desyrel), and others.
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

This combo cold-and-cough product (Theracaps) contains dextromethorphan, the cough suppressant that your body clears using an enzyme called CYP2D6. In lab studies, DMAA strongly blocks that same enzyme. So in theory, DMAA could let dextromethorphan build up, which may bring on drowsiness, dizziness, confusion, or in higher amounts even hallucinations and agitation.

Here's my bigger worry, though: DMAA is a powerful, banned stimulant, and this product already has phenylpropanolamine, a decongestant that raises blood pressure. Stacking two things that push blood pressure and heart rate up is risky on its own. Keep in mind the enzyme evidence is only test-tube data, not proven in people. Please skip DMAA entirely and check with your pharmacist before mixing anything with this medicine.

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
Moderate

STIMULANT DRUGS

2 of 2

Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine also falls under STIMULANT DRUGS.

1,3-DMAA is thought to have stimulant effects. There is concern that taking 1,3-DMAA with stimulant drugs might increase the risk of adverse cardiovascular effects. Some preliminary research shows that taking 1,3-DMAA 50 mg daily in combination with caffeine 250 mg daily does not increase respiratory rate, blood pressure, or other cardiovascular outcomes compared to taking caffeine alone in healthy men. However, a number of cardiovascular side effects have been reported for patients taking 1,3-DMAA in combination with other stimulants including caffeine. Theoretically, combining 1,3-DMAA with stimulant drugs might increase the risk of adverse cardiovascular effects. Some stimulant drugs include amphetamine, caffeine, diethylpropion (Tenuate), methylphenidate, phentermine (Ionamin), pseudoephedrine (Sudafed, others), and many others.
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

This cold and cough combo (Theracaps) contains phenylpropanolamine, which is itself a decongestant stimulant that tightens blood vessels and can nudge your blood pressure and heart rate up. DMAA is also a powerful stimulant, similar to amphetamine in how it revs up your body's fight-or-flight system. Stacking the two means you are doubling up on that pressor effect, and the worry here is added strain on your heart and blood vessels: think racing heartbeat, palpitations, headache, jitteriness, or a spike in blood pressure.

This concern is based on how these ingredients work (theoretical), not on hard studies of this exact pair, so I am not trying to scare you. But honestly, DMAA has been pulled by the FDA as unsafe, so the simplest move is to avoid it entirely. Please check with your pharmacist before combining anything like this.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Adverse Event Report. Jack3d. Natural MedWatch, May 28, 2011.
  2. Smith TB, Staub BA, Natarajan GM, et al. Acute myocardial infarction associated with dietary supplements containing 1,3-dimethylamylamine and Citrus aurantium. Tex Heart Inst J 2014;41(1):70-2. PubMed
  3. Armstrong M. Atrial Fibrillation with Rapid Ventricular Response following use of Dietary Supplement Containing 1,3 Dimethylamylamine and Caffeine. J Spec Oper Med. 2012 Winter;12(4):1-4. PubMed
  4. Bloomer RJ, Farney TM, Harvey IC, Alleman RJ. Safety profile of caffeine and 1,3-dimethylamylamine supplementation in healthy men. Hum Exp Toxicol. 2013 Nov;32(11):1126-36. PubMed
  5. Brown JA, Buckley NA. Toxicity from bodybuilding supplements and recreational use of products containing 1,3-dimethylamylamine. Med J Aust. 2013 May 6;198(8):414-5. PubMed
  6. Dolan SB, Gatch MB. Abuse liability of the dietary supplement dimethylamylamine. Drug Alcohol Depend. 2015 Jan 1;146:97-102. PubMed
  7. Forrester M. Exposures to 1,3-dimethylamylamine-containing products reported to Texas poison centers. Hum Exp Toxicol. 2013 Jan;32(1):18-23. PubMed
  8. Van Hout MC, Hearne E. "Plant or poison": A netnographic study of recreational use of 1,3-dimethylamylamine (DMAA). Int J Drug Policy. 2015 Dec;26(12):1279-81. 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-dmaa Also Interacts With Other Medications

1,3-dmaa has 320 moderate known drug interactions in our database — the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine one above is among them. If you take anything else, check it against the full list below.

Moderate 320 No known interaction 2,510 (incl. Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine)
Taking anything else?

Check Another of Your Medications Against 1,3-dmaa

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

Everything else you take

See Every Supplement That Interacts With Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine

This page covers 1,3-dmaa only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine page lists 282 supplements it has a documented interaction with, worst first, each one explained.

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

By severity: 14 major · 223 moderate · 45 minor.

From our pharmacist’s overview on the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine page

“Of everything on this page, ephedra worries me most for anyone using Theracaps (acetaminophen, dextromethorphan, phenylpropanolamine, and pyrilamine), because the decongestant in this cold formula is itself a stimulant. Adding ephedra or any of the 44 stimulant entries can push blood pressure and heart rate to unsafe levels.”

Reviewed by 2 · Jul 18, 2026

Open the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine interaction page

One more smart check

Taking 1,3-dmaa as Part of a Dietary Supplement Product? Check It for Interactions

We hold 94 real supplement products containing 1,3-dmaa, each one broken down to its full ingredient list — and combination products often carry several ingredients besides 1,3-dmaa. Your product may carry other ingredients that interact with Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine too, on top of 1,3-dmaa — 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 1,3-dmaa and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine 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-dmaa
Top half

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

29 days ago today
Medication Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine
Top 10%

#167 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-dmaa

What is 1,3-dmaa?

1,3-dmaa
  • Energy and stimulation
  • Pre-workout performance
  • Weight loss
  • Appetite suppression
  • Focus and concentration

DMAA (1,3-dimethylamylamine) is a synthetic stimulant that was sold in pre-workout and weight-loss supplements but has been linked to serious harm, including high blood pressure, heart problems, strokes, and deaths. The U.S. FDA and regulators in many countries have declared it illegal and unsafe in dietary supplements, so it should be avoided.

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

Other Drugs & 1,3-dmaa

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

0Major
320Moderate
0Minor
2,509No known interaction
320 Moderate 2,509 No interaction
Moderate

320 interactions

Showing 60 of 320 moderate interactions — see all 320 on the 1,3-dmaa page.

No interaction 2,509 drugs checked — show the list

We also checked 1,3-dmaa 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-dmaa list.

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

Can you take 1,3-dmaa with Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine?
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-dmaa and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine?
Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine belongs to more than one drug category, and 1,3-dmaa 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-dmaa and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine 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.