Drug & supplement interaction

1,3-dmba + Guaifenesin, Phenylpropanolamine

Guaifenesin, Phenylpropanolamine brand names: Entex LA, Miraphen PE, Dura-Vent, Guaifed, Guaifed-PD, and others.

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

1,3-dmba has a moderate interaction with Guaifenesin, Phenylpropanolamine. Theoretically, combining 1,3-DMBA with other stimulant drugs might increase the risk of cardiovascular toxicity.

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

1,3-dmba and Guaifenesin, Phenylpropanolamine

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

Moderate

STIMULANT DRUGS

Why this applies to Guaifenesin, Phenylpropanolamine

Guaifenesin, Phenylpropanolamine 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 know about this combo. Phenylpropanolamine is itself a stimulant decongestant. It narrows blood vessels and can nudge your blood pressure and heart rate up. The guaifenesin part is just an expectorant that thins mucus and doesn't really add to this concern. Pairing it with 1,3-DMBA, which is another stimulant, means you'd be stacking two blood-pressure-raising agents on top of each other.

The worry is added strain on your heart and blood vessels: a racing or pounding heartbeat, jitteriness, headache, or a spike in blood pressure. To be fair, this caution comes mostly from animal studies, so it's more theoretical than proven. Still, I'd steer clear of 1,3-DMBA entirely (the FDA considers it unsafe), and please run any combination past your pharmacist or doctor first.

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.

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 Guaifenesin, Phenylpropanolamine one above is one of them. If you take anything else, check it against the full list below.

Moderate 171 Minor 149 No known interaction 2,510 (incl. Guaifenesin, Phenylpropanolamine)
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 Guaifenesin, Phenylpropanolamine

This page covers 1,3-dmba only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Guaifenesin, Phenylpropanolamine page lists 62 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Ephedra (major), Peyote (major), Rauvolfia Vomitoria (major) and Sida Cordifolia (major).

By severity: 5 major · 44 moderate · 13 minor.

From our pharmacist’s overview on the Guaifenesin, Phenylpropanolamine page

“Ephedra is the entry I'd want anyone taking guaifenesin with phenylpropanolamine (Entex LA, Guaifed, Dura-Vent) to understand first. Phenylpropanolamine is a stimulant decongestant that can raise blood pressure on its own, and ephedra, along with three other stimulant herbs rated major, can stack on that effect and strain the heart.”

Reviewed by 2 · Jul 18, 2026

Open the Guaifenesin, Phenylpropanolamine interaction page

How much people look this up

Where 1,3-dmba and Guaifenesin, Phenylpropanolamine 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

#1,035 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Guaifenesin, Phenylpropanolamine
Top half

#1,019 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 Guaifenesin, Phenylpropanolamine, 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 Guaifenesin, Phenylpropanolamine supplement interactions › Every supplement checked against Guaifenesin, Phenylpropanolamine, 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 Guaifenesin, Phenylpropanolamine Together: Common Questions

Can you take 1,3-dmba with Guaifenesin, Phenylpropanolamine?
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 1,3-dmba and Guaifenesin, Phenylpropanolamine 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 Guaifenesin, Phenylpropanolamine and 1,3-dmba?

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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.