Drug & supplement interaction

N,n-dmpea + Timolol

Timolol brand names: Blocadren, Timol, Timoptic.

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

N,n-dmpea has a moderate interaction with Timolol. In vitro research shows that N,N-DMPEA strongly inhibits cytochrome P450 2D6 (CYP2D6).

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

N,n-dmpea and Timolol

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

Moderate

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

Why this applies to Timolol

Timolol falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group N,n-dmpea interacts with.

In vitro research shows that N,N-DMPEA strongly inhibits cytochrome P450 2D6 (CYP2D6). Theoretically, concomitant use with drugs metabolized by CYP2D6 might increase the risk for adverse effects from these drugs.
Some drugs metabolized by CYP2D6 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 thing with this pairing: your body partly clears timolol using a liver enzyme called CYP2D6. In lab studies, N,N-DMPEA appears to block that enzyme. If it does the same in people, timolol could clear more slowly and build up in your system. Timolol is a beta blocker, so more of it than expected might mean a heart rate that runs too slow, lightheadedness, unusual tiredness, or blood pressure that dips lower than you want.

I want to be honest about the evidence, though. This is based only on test-tube data, not real human studies, and N,N-DMPEA itself is poorly studied. So this is a theoretical concern, not a proven one. Since timolol affects your heart, please run this combination by 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

N,n-dmpea Also Interacts With Other Medications

N,n-dmpea has 192 moderate known drug interactions in our database — the Timolol one above is one of them. If you take anything else, check it against the full list below.

Moderate 192 No known interaction 2,638 (incl. Timolol)
Taking anything else?

Check Another of Your Medications Against N,n-dmpea

Covers the 2,830 medications we’ve checked against N,n-dmpea. Pick one to open its full report.

From our Q&A

Questions About N,n-dmpea or Timolol

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers N,n-dmpea or Timolol, 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 Timolol

This page covers N,n-dmpea only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Timolol page lists 183 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Indian Snakeroot (major) and Tyramine (major).

By severity: 5 major · 151 moderate · 27 minor.

From our pharmacist’s overview on the Timolol page

“The supplement list for timolol (Blocadren, Timoptic) calls for genuine care, starting with its five major-rated entries. Timolol is a beta-blocker that slows the heart and lowers blood pressure, and even the eye-drop form absorbs enough to matter.”

Reviewed by 2 · Jul 18, 2026

Open the Timolol interaction page

How much people look this up

Where N,n-dmpea and Timolol 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 N,n-dmpea
Steady interest

#1,404 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Timolol
Steady interest

#1,639 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 N,n-dmpea

What is N,n-dmpea?

  • Mood or energy support
  • Pre-workout or stimulant effect
  • Cognitive or focus support

N,N-DMPEA (N,N-dimethylphenethylamine) is a synthetic relative of phenethylamine sometimes marketed in stimulant or pre-workout supplements. There is very little reliable human research on its effects or safety, and it is not a well-established dietary ingredient, so it should be approached with real caution.

Read the full N,n-dmpea monograph & all interactions
Medication

About Timolol

What Is Timolol Used For?

Brand names: Blocadren, Timol, Timoptic

Timolol is available in ophthalmic (eye) forms and as an oral tablet, and each form has its own approved uses. Ophthalmic formulations — including Betimol, Istalol, Timolol GFS, Timolol hemihydrate, Timolol Maleate eye drops, and Timolol Maleate Ophthalmic Gel Forming Solution — are used to lower elevated intraocular pressure (pressure inside the eye) in people with ocular hypertension or open-angle glaucoma.

Timolol Maleate tablets are used orally for three separate conditions: treating high blood pressure (alone or combined with other blood pressure medicines), reducing the risk of death and repeat heart attack in people who have survived a heart attack and are clinically stable, and preventing migraine headaches.

See full Timolol drug information
Keep checking

Other Drugs & N,n-dmpea

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

0Major
192Moderate
0Minor
2,637No known interaction
192 Moderate 2,637 No interaction
Moderate

192 interactions

Showing 60 of 192 moderate interactions — see all 192 on the N,n-dmpea page.

No interaction 2,637 drugs checked — show the list

We also checked N,n-dmpea against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,637 medications checked with no known interaction — see the full N,n-dmpea list.

See the full N,n-dmpea interactions page
See every supplement checked against Timolol, 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
N,n-dmpea monograph › Uses, safety, and every drug interaction in one place Timolol supplement interactions › Every supplement checked against Timolol, ranked by severity Timolol 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 N,n-dmpea and Timolol Together: Common Questions

Can you take N,n-dmpea with Timolol?
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 N,n-dmpea and Timolol 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 Timolol and N,n-dmpea?

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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.