Drug & supplement interaction

Phenethylamine (pea) + Dextromethorphan, Methscopolamine, Phenylephrine

Dextromethorphan, Methscopolamine, Phenylephrine brand name: DA Chewable.

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

Phenethylamine (pea) has a moderate interaction with Dextromethorphan, Methscopolamine, Phenylephrine. Theoretically, combining serotonergic drugs with phenethylamine might increase the risk of serotonergic adverse effects.

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

Phenethylamine (pea) and Dextromethorphan, Methscopolamine, Phenylephrine

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

Moderate

SEROTONERGIC DRUGS

Why this applies to Dextromethorphan, Methscopolamine, Phenylephrine

Dextromethorphan, Methscopolamine, Phenylephrine falls under SEROTONERGIC DRUGS — the group Phenethylamine (pea) interacts with.

Theoretically, combining serotonergic drugs with phenethylamine might increase the risk of serotonergic adverse effects.
Animal research shows that phenethylamine increases levels of serotonin, norepinephrine, and dopamine. Theoretically, combining serotonergic drugs with phenethylamine might increase the risk of additive serotonergic adverse effects, including serotonin syndrome and cerebral vasoconstrictive disorders. However, low-quality clinical research has used phenethylamine with selegiline, a monoamine oxidase inhibitor (MAOI), with apparent safety.
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 contains dextromethorphan, which nudges serotonin levels upward in the brain. Phenethylamine (PEA) does something similar in animal studies, raising serotonin, dopamine, and norepinephrine. So in theory, stacking the two could add up and raise the small chance of too much serotonin activity. Signs to watch for would be agitation, a racing heart, sweating, shivering, or muscle twitching.

I want to be honest though: this concern comes from lab and animal data, not solid human studies, so it's more of a caution than a proven problem. One extra wrinkle, the phenylephrine here also bumps blood pressure, and PEA can too, so that's worth keeping in mind. Please run this past your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Singhal AB, Caviness VS, Begleiter AF, et al. Cerebral vasoconstriction and stroke after use of serotonergic drugs. Neurology 2002;58:130-3. PubMed
  2. Sabelli H, Fink P, Fawcett J, et al. Sustained antidepressant effect of PEA replacement. J Neuropsychiatry Clin Neurosci. 1996;8(2):168-71.
  3. Xie Z, Miller G. Beta-phenylehtylamine alters monoamine transporter function via trace amine-associated receptor 1: implication for modulatory roles of trace amines in brain. J Pharmacol Exp Ther. 2008;325(2):617-28.
  4. Nakamura M, Ishii A, Nakahara D. Characterization of beta-phenyltheylamine-induced monoamine release in rat nucleus accumbens: a microdialysis study. Eur J Pharmacol. 1998;349(2-3):163-9.
  5. Bailey B, Philips S, Boulton A. In vivo release of endogenous dopamine, 5-hydroxytryptamine and some of their metabolites from rat caudate nucleus by phenylethylamine. Neurochem Res. 1987;12(2):173-8. 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

Phenethylamine (pea) Also Interacts With Other Medications

Phenethylamine (pea) has 186 moderate known drug interactions in our database — the Dextromethorphan, Methscopolamine, Phenylephrine one above is one of them. If you take anything else, check it against the full list below.

Moderate 186 No known interaction 2,644 (incl. Dextromethorphan, Methscopolamine, Phenylephrine)
Taking anything else?

Check Another of Your Medications Against Phenethylamine (pea)

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

Everything else you take

See Every Supplement That Interacts With Dextromethorphan, Methscopolamine, Phenylephrine

This page covers Phenethylamine (pea) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Dextromethorphan, Methscopolamine, Phenylephrine page lists 220 supplements it has a documented interaction with, worst first, each one explained.

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

By severity: 10 major · 166 moderate · 44 minor.

From our pharmacist’s overview on the Dextromethorphan, Methscopolamine, Phenylephrine page

“Dextromethorphan with methscopolamine and phenylephrine (DA Chewable) packs a cough suppressant, a drying agent, and a decongestant into one tablet, which gives supplements several distinct ways to cause trouble, so I treat this as a list deserving real caution. Grapefruit can drive levels of the drug up by blocking its breakdown, St.”

Reviewed by 2 · Jul 18, 2026

Open the Dextromethorphan, Methscopolamine, Phenylephrine interaction page

One more smart check

Taking Phenethylamine (pea) as Part of a Dietary Supplement Product? Check It for Interactions

We hold 208 real supplement products containing Phenethylamine (pea), each one broken down to its full ingredient list — and combination products often carry several ingredients besides Phenethylamine (pea). Your product may carry other ingredients that interact with Dextromethorphan, Methscopolamine, Phenylephrine too, on top of Phenethylamine (pea) — 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 Phenethylamine (pea) and Dextromethorphan, Methscopolamine, 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 Phenethylamine (pea)
Top half

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

29 days ago today
Medication Dextromethorphan, Methscopolamine, Phenylephrine
Top 25%

#472 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 Phenethylamine (pea)

What is Phenethylamine (pea)?

Phenethylamine (pea)
  • Mood support
  • Focus and concentration
  • Energy and pre-workout boost
  • Feeling of well-being
  • Athletic performance

Phenethylamine (PEA) is a natural compound made in the body and found in foods like chocolate; supplements are marketed for mood, focus, and energy. Reliable human research on the supplement is very limited, and it may raise blood pressure or heart rate, so people with heart or blood pressure problems should be cautious and check with a pharmacist or doctor first.

Read the full Phenethylamine (pea) monograph & all interactions
Keep checking

Other Drugs & Phenethylamine (pea)

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

0Major
186Moderate
0Minor
2,643No known interaction
186 Moderate 2,643 No interaction
Moderate

186 interactions

Showing 60 of 186 moderate interactions — see all 186 on the Phenethylamine (pea) page.

No interaction 2,643 drugs checked — show the list

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

Showing the 60 most looked-up of 2,643 medications checked with no known interaction — see the full Phenethylamine (pea) list.

See the full Phenethylamine (pea) interactions page
See every supplement checked against Dextromethorphan, Methscopolamine, 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
Phenethylamine (pea) monograph › Uses, safety, and every drug interaction in one place Dextromethorphan, Methscopolamine, Phenylephrine supplement interactions › Every supplement checked against Dextromethorphan, Methscopolamine, 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 Phenethylamine (pea) and Dextromethorphan, Methscopolamine, Phenylephrine Together: Common Questions

Can you take Phenethylamine (pea) with Dextromethorphan, Methscopolamine, 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 Phenethylamine (pea) and Dextromethorphan, Methscopolamine, 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 Dextromethorphan, Methscopolamine, Phenylephrine and Phenethylamine (pea)?

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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.