Drug & supplement interaction

Phenpromethamine + Gabapentin

Gabapentin brand names: Neurontin, Gralise.

No Known Interaction
Medically reviewed by · Updated June 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Phenpromethamine and Gabapentin in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Phenpromethamine and Gabapentin

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Gabapentin and Phenpromethamine in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Phenpromethamine safety at a glance

Phenpromethamine overall Avoid This is an unapproved synthetic stimulant that should not be used as a supplement.
Pregnancy Possibly Unsafe When used orally. Certain stimulants, especially when used in combination with other stimulants or intensive exercise, have been associated with cardiovascular... Read the full pregnancy detail
Breastfeeding Possibly Unsafe When used orally. Certain stimulants, especially when used in combination with other stimulants or intensive exercise, have been associated with cardiovascular... Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Gabapentin and Phenpromethamine? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Gabapentin

Interactions in our licensed database are recorded against drug classes, not just single drug names. Gabapentin is filed under 4 classifications — including anticonvulsants, cns depressants, oral drugs. Phenpromethamine has documented interactions with 1 drug class — the most serious being stimulant drugs (moderate) — and none of Gabapentin’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Phenpromethamine Does Interact With Other Medications

Phenpromethamine has 172 moderate known drug interactions in our database — Gabapentin isn’t one of them. If you take anything else, check it against the full list below.

Moderate 172 No known interaction 2,658 (incl. Gabapentin)
Taking anything else?

Check Another of Your Medications Against Phenpromethamine

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

What to actually watch for

What Gabapentin’s Own FDA Label Lists

This is not an interaction — none of it involves Phenpromethamine. These are the most notable effects listed in the ADVERSE REACTIONS section of Gabapentin’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you take both. 10 of them are worth acting on rather than waiting out — marked below.

  • Dependence or withdrawal symptoms Worth acting on
  • Thoughts of self-harm Worth acting on
  • Severe muscle breakdown Worth acting on
  • Memory problems Worth acting on
  • Low sodium Worth acting on
  • Unsteadiness Worth acting on
  • Yellowing of the skin or eyes Worth acting on
  • High blood sugar Worth acting on
  • Confusion Worth acting on
  • A severe skin reaction Worth acting on

Showing the 10 most notable of 42 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

From the ADVERSE REACTIONS section of the FDA label for Gabapentin. Read the label on DailyMed › Where a percentage is shown, it is the share of 361,481 voluntary FDA FAERS reports for Gabapentin that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Phenpromethamine’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Phenpromethamine side to compare — that is a limit of the record, not a statement that Phenpromethamine has no side effects.

Special populations

Phenpromethamine in Pregnancy & Breastfeeding

Pregnancy And Lactation Possibly Unsafe

When used orally. Certain stimulants, especially when used in combination with other stimulants or intensive exercise, have been associated with cardiovascular events such as stroke and cardiac arrest. Avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

From our Q&A

Questions About Phenpromethamine or Gabapentin

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

This page covers Phenpromethamine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Gabapentin page lists 106 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), Beer (major), Gamma-hydroxybutyrate (ghb) (major) and Kava (major).

By severity: 7 major · 82 moderate · 17 minor.

From our pharmacist’s overview on the Gabapentin page

“Gabapentin (Neurontin, Gralise) calms overactive nerves, which means it already slows your nervous system down, and that is exactly what 78 of the 106 supplements on this list also do. So the dominant risk here is sedation stacked on sedation, extra drowsiness at best and dangerously slowed breathing at worst, and with seven entries ra…”

Reviewed by 2 · Jul 18, 2026

Open the Gabapentin interaction page

How much people look this up

Where Phenpromethamine and Gabapentin 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 Phenpromethamine
Steady interest

#1,118 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Gabapentin
Top 5%

#42 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Phenpromethamine reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Phenpromethamine and Gabapentin records this page draws on were last updated June 22, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Phenpromethamine

What is Phenpromethamine?

  • Nasal decongestion (historical)
  • Stimulant effects (misuse)
  • Pre-workout 'energy' (illegally added to some products)

Phenpromethamine is a synthetic stimulant drug, not a herb or legitimate dietary supplement. It has been found illegally added to some sports and weight-loss supplements, and it is not approved for use in the United States. You should avoid any product that lists it as an ingredient and talk to a pharmacist or doctor.

Not applicable; phenpromethamine is a synthetic chemical, not a plant part · Historically found as a nasal inhaler; not a legitimate dietary supplement ingredient

An interaction check asks whether these two react with each other — it does not ask whether Phenpromethamine is a good idea for someone in your situation. Here is what our Phenpromethamine record says about it on its own.

Phenpromethamine: dosing

There is no established or recommended dose of phenpromethamine for supplement use. It is not an approved supplement ingredient, and any amount found in products is unregulated and potentially unsafe.Because the amount in spiked products is unknown and uncontrolled, no dose can be considered safe. The best advice is to avoid products that contain it entirely.

From our Phenpromethamine monograph — the full record covers uses, side effects and every documented interaction.

Read the full Phenpromethamine monograph & all interactions
Medication

About Gabapentin

What Is Gabapentin Used For?

Brand names: Neurontin, Gralise

Gabapentin (brands include Neurontin, Relgaabi, Gabarone, Gralise, and Horizant) is primarily used to manage postherpetic neuralgia (PHN) — the nerve pain that lingers after a shingles outbreak — in adults. Neurontin, Relgaabi, Gabarone, and gabapentin capsules, tablets, and oral solution are also used as add-on therapy for partial onset seizures (a type of epilepsy) in adults and children aged 3 and older.

Horizant (gabapentin enacarbil extended-release tablet) has two specific approvals: treatment of moderate-to-severe primary restless legs syndrome (RLS) in adults, and management of postherpetic neuralgia in adults. Horizant is not recommended for people who need to sleep during the day and stay awake at night. Gralise is approved only for postherpetic neuralgia and cannot be substituted for other gabapentin products due to its different release profile.

Most-Reported Side Effects for Gabapentin

From FAERS, the FDA’s public side-effect reporting system (361,481 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 24,972 reports
Nausea 22,728 reports
Diarrhea 18,114 reports
Headache 17,897 reports
Dizziness 16,238 reports
See full Gabapentin drug information
Keep checking

Other Drugs & Phenpromethamine

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

0Major
172Moderate
0Minor
2,657No known interaction
172 Moderate 2,657 No interaction
Moderate

172 interactions

Showing 60 of 172 moderate interactions — see all 172 on the Phenpromethamine page.

No interaction 2,657 drugs checked — show the list

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

Showing the 60 most looked-up of 2,657 medications checked with no known interaction — see the full Phenpromethamine list.

See the full Phenpromethamine interactions page
See every supplement checked against Gabapentin, ranked by severity
Evidence & sources

Phenpromethamine References

The 2 references that drive our Phenpromethamine monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Venhuis B, Keizers P, van Riel A, de Kaste D. A cocktail of synthetic stimulants found in a dietary supplement associated with serious adverse events. Drug Test Anal. 2014 Jun;6(6):578-81. doi: 10.1002/dta.1664. Epub 2014 May 6. PubMed
  2. Cohen PA, Travis JC, Vanhee C, Ohana D, Venhuis BJ. Nine prohibited stimulants found in sports and weight loss supplements: deterenol, phenpromethamine (Vonedrine), oxilofrine, octodrine, beta-methylphenylethylamine (BMPEA), 1,3-dimethylamylamine (1,3-DMA

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Phenpromethamine and Gabapentin Together: Common Questions

Is it safe to take Phenpromethamine with Gabapentin?
We do not list a known interaction between Phenpromethamine and Gabapentin. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
How was the Phenpromethamine and Gabapentin combination checked?
Interactions in our licensed database are recorded against drug classes. Gabapentin is filed under 4 classifications, and Phenpromethamine has documented interactions with 1 drug class — none of Gabapentin's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Phenpromethamine interact with any other medications?
Yes. Phenpromethamine has 172 documented drug interactions in our database — Gabapentin is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Gabapentin interact with any supplements?
Yes. Gabapentin has documented interactions with 106 supplements in our database — Phenpromethamine is not one of them. The Gabapentin interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Phenpromethamine monograph Uses, safety profile, and every drug interaction in one place Gabapentin drug information The full plain-English guide to this medication Gabapentin supplement interactions Every supplement checked against Gabapentin, 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 References The 2 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Gabapentin and Phenpromethamine?

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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.