Drug & supplement interaction

Octopamine + Phentermine

Phentermine brand names: Adipex-P, Fastin, T Diet, Phentride, Obenix, and others.

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

Octopamine has a minor interaction with Phentermine. Octopamine is thought to have stimulant effects.

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

Octopamine and Phentermine

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

Minor

STIMULANT DRUGS

Why this applies to Phentermine

Phentermine falls under STIMULANT DRUGS — the group Octopamine interacts with.

Octopamine is thought to have stimulant effects. Theoretically, taking octopamine with other stimulant drugs might increase the risk of hypertension and adverse cardiovascular effects.
Some stimulant drugs include amphetamine, caffeine, diethylpropion (Tenuate), methylphenidate, phentermine (Ionamin), pseudoephedrine (Sudafed, others), and many others.
Severity Minor 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 keep in mind: phentermine is itself a stimulant that speeds up your heart and can nudge your blood pressure up. Octopamine acts in a similar way, working on those same adrenaline-type pathways. So when you stack the two together, you're essentially doubling up on stimulant activity. Theoretically, that could mean a faster or pounding heartbeat, higher blood pressure, jitteriness, trouble sleeping, or feeling anxious and wired.

I want to be honest about the evidence, though. This concern is based on how these compounds behave in the lab and on basic pharmacology, not on strong human studies, and it's rated as a minor, possible interaction. Still, since both touch the heart, I'd run it by your doctor or pharmacist before combining them, especially if you have any blood pressure or heart concerns.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Pawar RS, Grundel E. Overview of regulation of dietary supplements in the USA and issues of adulteration with phenethylamines (PEAs). Drug Test Anal 2017;9:500-517. 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

Octopamine Also Interacts With Other Medications

Octopamine has 181 moderate, 170 minor known drug interactions in our database — the Phentermine one above is one of them. If you take anything else, check it against the full list below.

Moderate 181 Minor 170 No known interaction 2,479 (incl. Phentermine)
Taking anything else?

Check Another of Your Medications Against Octopamine

Covers the 2,830 medications we’ve checked against Octopamine. Pick one to open its full report.

From our Q&A

Questions About Octopamine or Phentermine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Octopamine or Phentermine, 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 Phentermine

This page covers Octopamine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phentermine page lists 61 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 · 43 moderate · 13 minor.

From our pharmacist’s overview on the Phentermine page

“Ephedra is the pairing I most want anyone taking phentermine (Adipex-P) to know about. Phentermine is itself a stimulant appetite suppressant that raises heart rate and blood pressure, and ephedra piles the same cardiovascular strain on top of it.”

Reviewed by 2 · Jul 18, 2026

Open the Phentermine interaction page

One more smart check

Taking Octopamine as Part of a Dietary Supplement Product? Check It for Interactions

We hold 118 real supplement products containing Octopamine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Octopamine. Your product may carry other ingredients that interact with Phentermine too, on top of Octopamine — 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 Octopamine and Phentermine 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 Octopamine
Steady interest

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

29 days ago today
Medication Phentermine
Top 25%

#290 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 Octopamine

What is Octopamine?

  • Weight loss and fat burning
  • Boosting energy
  • Athletic performance
  • Appetite suppression

Octopamine is a stimulant-like compound found in small amounts in some plants (such as bitter orange) and made naturally in the body. It is marketed mostly in weight-loss and sports supplements, but human evidence that it actually helps with fat loss or performance is very limited. Because it can affect the heart and blood pressure and is banned in some sports, talk to a pharmacist or doctor before using it.

Read the full Octopamine monograph & all interactions
Medication

About Phentermine

What Is Phentermine Used For?

Brand names: Adipex-P, Fastin, T Diet, Phentride, Obenix, Pbc Phentride, Pbw Phentride, Phentrol #3, Ionamin, Phentrol #6, Phentrol #2, Phentrol #5, Phentrol, Obermine, Phentermine, Suprenza

Phentermine is approved as a short-term addition to a weight-loss program — not a standalone treatment. It is used alongside reduced-calorie eating, increased physical activity, and behavior changes to help manage obesity in adults whose body mass index (BMI) is 30 kg/m² or higher, or 27 kg/m² or higher when other risk factors such as controlled high blood pressure, diabetes, or high cholesterol (hyperlipidemia) are also present.

All available phentermine products — including Adipex-P, Lomaira, and various generic capsules and tablets — share this same FDA-approved use. Lomaira tablets are specifically dosed to be taken three times daily before meals, while other formulations are generally taken once daily. Treatment is intended to last only a few weeks.

See full Phentermine drug information
Keep checking

Other Drugs & Octopamine

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

0Major
181Moderate
170Minor
2,478No known interaction
181 Moderate 170 Minor 2,478 No interaction
Moderate

181 interactions

Showing 60 of 181 moderate interactions — see all 181 on the Octopamine page.

Minor

170 interactions

Showing 60 of 170 minor interactions — see all 170 on the Octopamine page.

No interaction 2,478 drugs checked — show the list

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

Showing the 60 most looked-up of 2,478 medications checked with no known interaction — see the full Octopamine list.

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

Can you take Octopamine with Phentermine?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Octopamine and Phentermine interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Phentermine and Octopamine?

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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.