Drug & supplement interaction

Beta-methylphenethylamine (bmpea) + Erythromycin

Erythromycin brand names: Erythro S, PCE, E-Mycin, Erythro-ES, EryPed Chewable, and others.

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

Beta-methylphenethylamine (bmpea) has a moderate interaction with Erythromycin. Theoretically, BMPEA might increase the levels and clinical effects of CYP3A4 substrates.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Beta-methylphenethylamine (bmpea) and Erythromycin

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

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Erythromycin

Erythromycin falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Beta-methylphenethylamine (bmpea) interacts with.

Theoretically, BMPEA might increase the levels and clinical effects of CYP3A4 substrates.
In vitro research shows that BMPEA inhibits CYP3A4 by up to 37%.
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 basic idea with this pairing. Erythromycin is partly cleared by a liver enzyme called CYP3A4, and lab studies suggest BMPEA can slow that same enzyme down (by roughly a third in test-tube experiments). If that happens in the body, erythromycin could build up a bit higher than usual. With this antibiotic, that can mean more stomach upset, nausea, cramping, or diarrhea, and in rarer cases changes in your heart rhythm (a QT effect).

Keep in mind this is theoretical, based on lab work rather than real patient cases, so I don't want to alarm you. That said, BMPEA itself is an unapproved stimulant with real heart concerns, so I'd skip it and check with your pharmacist or doctor before mixing the two.

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

Beta-methylphenethylamine (bmpea) Also Interacts With Other Medications

Beta-methylphenethylamine (bmpea) has 812 moderate known drug interactions in our database — the Erythromycin one above is one of them. If you take anything else, check it against the full list below.

Moderate 812 No known interaction 2,018 (incl. Erythromycin)
Taking anything else?

Check Another of Your Medications Against Beta-methylphenethylamine (bmpea)

Covers the 2,830 medications we’ve checked against Beta-methylphenethylamine (bmpea). Pick one to open its full report.

From our Q&A

Questions About Beta-methylphenethylamine (bmpea) or Erythromycin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Beta-methylphenethylamine (bmpea) or Erythromycin, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Erythromycin

This page covers Beta-methylphenethylamine (bmpea) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Erythromycin page lists 204 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Beer (major) and Cesium (major).

By severity: 11 major · 153 moderate · 40 minor.

From our pharmacist’s overview on the Erythromycin page

“Erythromycin calls for more supplement caution than most antibiotics, and the reason is one liver enzyme, CYP3A4. Erythromycin both blocks that enzyme and is broken down by it, so grapefruit can push erythromycin levels up while St.”

Reviewed by 2 · Jul 18, 2026

Open the Erythromycin interaction page

How much people look this up

Where Beta-methylphenethylamine (bmpea) and Erythromycin 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 Beta-methylphenethylamine (bmpea)
Steady interest

#1,274 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Erythromycin
Top 25%

#375 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 Beta-methylphenethylamine (bmpea)

What is Beta-methylphenethylamine (bmpea)?

  • Weight loss
  • Pre-workout energy
  • Athletic performance
  • Appetite suppression
  • Mental focus

Beta-methylphenethylamine (BMPEA) is a synthetic stimulant chemically similar to amphetamine that has been found in some weight-loss and sports supplements, often without being clearly listed on the label. It is not an approved or well-studied dietary ingredient, and regulators have warned that it may carry real cardiovascular risks. Because of safety concerns and the lack of human research, it is best avoided.

Read the full Beta-methylphenethylamine (bmpea) monograph & all interactions
Medication

About Erythromycin

What Is Erythromycin Used For?

Brand names: Erythro S, PCE, E-Mycin, Erythro-ES, EryPed Chewable, Eryc, Ery-Tab, Rythro Enca, Erythro E-C, Erythro Base, Ilosone, Ilotycin

Erythromycin treats bacterial infections caused by susceptible organisms. Oral and intravenous forms are used for upper and lower respiratory tract infections, skin and soft-tissue infections, pertussis (whooping cough), Legionnaires' disease, sexually transmitted infections (gonorrhea, syphilis, chlamydia), listeriosis, and other conditions. Erythrocin Lactobionate IV and erythromycin lactobionate injection are specifically for patients who cannot take oral medication or who need rapid, high blood levels due to severe infection — IV therapy should be switched to oral as soon as appropriate.

Erythromycin topical solution 2% and Ery 2% Pads (swabs) are indicated only for the topical treatment of acne vulgaris (acne) and are applied directly to the skin — they are not used for internal infections.

See full Erythromycin drug information
Keep checking

Other Drugs & Beta-methylphenethylamine (bmpea)

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

0Major
812Moderate
0Minor
2,017No known interaction
812 Moderate 2,017 No interaction
Moderate

812 interactions

Showing 60 of 812 moderate interactions — see all 812 on the Beta-methylphenethylamine (bmpea) page.

No interaction 2,017 drugs checked — show the list

We also checked Beta-methylphenethylamine (bmpea) against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,017 medications checked with no known interaction — see the full Beta-methylphenethylamine (bmpea) list.

See the full Beta-methylphenethylamine (bmpea) interactions page
See every supplement checked against Erythromycin, 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
Beta-methylphenethylamine (bmpea) monograph › Uses, safety, and every drug interaction in one place Erythromycin supplement interactions › Every supplement checked against Erythromycin, ranked by severity Erythromycin drug information › The full plain-English guide to this medication 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 Beta-methylphenethylamine (bmpea) and Erythromycin Together: Common Questions

Can you take Beta-methylphenethylamine (bmpea) with Erythromycin?
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 Beta-methylphenethylamine (bmpea) and Erythromycin 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 Erythromycin and Beta-methylphenethylamine (bmpea)?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.