Drug & supplement interaction

1,3-dmaa + Aspirin, Codeine Phosphate, Methocarbamol

Aspirin, Codeine Phosphate, Methocarbamol brand name: Robaxisal C.

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

1,3-dmaa has a moderate interaction with Aspirin, Codeine Phosphate, Methocarbamol. 1,3-DMAA strongly inhibits cytochrome P450 2D6 (CYP2D6) enzymes in vitro.

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

1,3-dmaa and Aspirin, Codeine Phosphate, Methocarbamol

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

Moderate

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

Why this applies to Aspirin, Codeine Phosphate, Methocarbamol

Aspirin, Codeine Phosphate, Methocarbamol 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

Here's the wrinkle with this combo product: the codeine part is a prodrug. Your body has to convert codeine into morphine using an enzyme called CYP2D6, and that's what gives the pain relief. Lab studies suggest 1,3-DMAA blocks that very enzyme. So in theory, less of your codeine would turn into active morphine, meaning you might get weaker pain relief than expected.

I'll be honest, this is only based on test-tube data, so it's more theoretical than proven. The bigger concern is DMAA itself, which is a banned, risky stimulant that can spike blood pressure and heart rate. I wouldn't use it at all. Please talk with your pharmacist or doctor before mixing anything here.

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

1,3-dmaa Also Interacts With Other Medications

1,3-dmaa has 320 moderate known drug interactions in our database — the Aspirin, Codeine Phosphate, Methocarbamol one above is one of them. If you take anything else, check it against the full list below.

Moderate 320 No known interaction 2,510 (incl. Aspirin, Codeine Phosphate, Methocarbamol)
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 Aspirin, Codeine Phosphate, Methocarbamol

This page covers 1,3-dmaa only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Aspirin, Codeine Phosphate, Methocarbamol page lists 328 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 Danshen (major).

By severity: 12 major · 282 moderate · 34 minor.

From our pharmacist’s overview on the Aspirin, Codeine Phosphate, Methocarbamol page

“Alcohol is the single riskiest thing to combine with Robaxisal C (aspirin, codeine phosphate, and methocarbamol). Beer and wine both carry major ratings backed by solid human evidence, because codeine and methocarbamol already slow breathing and reflexes, and alcohol deepens that sedation.”

Reviewed by 2 · Jul 18, 2026

Open the Aspirin, Codeine Phosphate, Methocarbamol 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 Aspirin, Codeine Phosphate, Methocarbamol 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 Aspirin, Codeine Phosphate, Methocarbamol 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

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

29 days ago today
Medication Aspirin, Codeine Phosphate, Methocarbamol
Top 25%

#561 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 Aspirin, Codeine Phosphate, Methocarbamol, 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 Aspirin, Codeine Phosphate, Methocarbamol supplement interactions › Every supplement checked against Aspirin, Codeine Phosphate, Methocarbamol, 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 Aspirin, Codeine Phosphate, Methocarbamol Together: Common Questions

Can you take 1,3-dmaa with Aspirin, Codeine Phosphate, Methocarbamol?
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-dmaa and Aspirin, Codeine Phosphate, Methocarbamol 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 Aspirin, Codeine Phosphate, Methocarbamol and 1,3-dmaa?

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.