Drug & supplement interaction

Gamma Butyrolactone (gbl) + Topiramate

Topiramate brand names: Topamax, Trokendi XR, Qudexy XR, Eprontia.

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

Topiramate falls into 3 drug categories that Gamma Butyrolactone (gbl) can interact with; the most serious is rated moderate. Theoretically, concomitant use of GBL with CNS depressants may potentiate respiratory and CNS depression.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Gamma Butyrolactone (gbl) and Topiramate

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Gamma Butyrolactone (gbl) interacts with whole categories of medication. Topiramate falls into 3 of those categories, so it can interact with Gamma Butyrolactone (gbl) in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CNS DEPRESSANTS

1 of 3

Why this applies to Topiramate

Topiramate falls under CNS DEPRESSANTS — the group Gamma Butyrolactone (gbl) interacts with.

Theoretically, concomitant use of GBL with CNS depressants may potentiate respiratory and CNS depression.
GBL is metabolized to gamma-hydroxybutyrate (GHB). Concomitant use of CNS depressants with GHB may cause serious CNS and respiratory depression.
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

Let me be very direct here: GBL is not a supplement, it's a toxic solvent your body turns into GHB, a heavy sedative. It's illegal to sell for human use, and on its own it can cause coma, seizures, and death. Please don't take it. If you're struggling with sleep, anxiety, or substance use, your doctor or pharmacist can help safely.

Topiramate already slows down activity in the brain to control seizures, and it commonly causes drowsiness, dizziness, confusion, trouble concentrating, and slowed thinking. Stacking GBL's sedating effect on top of that could deepen this slowing and, in a serious case, depress your breathing. This concern is theoretical and based on anecdotal reports, but given how dangerous GBL is by itself, the safest move is simple: avoid it entirely and talk with your pharmacist about any real concerns.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Anon. Important message for health professionals: Report serious adverse events associated with dietary supplements containing GBL, GHB or BD. Food and Drug Administration, Rockville, MD. August 25, 1999. Available at: http://vm.cfsan.fda.gov/~dms/mwg
  2. Anon. Multistate outbreak of poisonings associated with illicit use of gamma hydroxy butyrate. JAMA 1991;265:447-8. DOI
  3. Product information for Xyrem. Jazz Pharmaceuticals, Inc. Palo Alto, CA. March 2022.
Moderate

ANTICONVULSANTS

2 of 3

Topiramate also falls under ANTICONVULSANTS.

Theoretically, concomitant use of GBL with certain anticonvulsants may potentiate respiratory and central nervous system (CNS) depression or increase the risk of seizures.
GBL is metabolized to gamma-hydroxybutyrate (GHB). Concomitant use of anticonvulsants that have sedative effects with GHB may cause serious CNS and respiratory depression. GHB can also cause seizures and might reduce the effectiveness of anticonvulsants.
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

First, an important heads-up: GBL is not a supplement. It's a toxic industrial solvent that your body turns into GHB, a heavy sedative. It's illegal for human use and can cause coma, seizures, and death on its own. So this isn't really about a typical drug interaction, it's about a dangerous substance.

That said, here's the concern when it's combined with topiramate. Topiramate already can make people feel drowsy, foggy, or slowed down. Stacking it with GHB's strong sedation could deepen that, leading to dangerous breathing problems and loss of consciousness. Oddly, GHB can also trigger seizures and may work against topiramate's seizure control. This is theoretical and based only on anecdotal reports, but the bottom line is simple: please don't use GBL, and talk to your doctor or pharmacist for safe help.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Anon. Multistate outbreak of poisonings associated with illicit use of gamma hydroxy butyrate. JAMA 1991;265:447-8. DOI
  2. Carotenuto A, De Feo V, Fattorusso E, et al. The flavonoids of Allium ursinum. Phytochem 1996;41:531-6. PubMed
  3. Product information for Xyrem. Jazz Pharmaceuticals, Inc. Palo Alto, CA. March 2022.
Moderate

TOPIRAMATE (Topamax)

3 of 3
Concomitant use of GBL with topiramate may potentiate adverse effects.
GBL is metabolized to gamma-hydroxybutyrate (GHB). Concomitant use of topiramate with GHB may increase blood levels of GHB. In one case report, a patient regularly taking GHB 4.5 grams twice nightly was hospitalized after initiating treatment with topiramate 25 mg daily. Symptoms included confusion, muscle jerking, miosis, and coma. Plasma levels of GHB were 2.5-fold higher than when GHB was given alone. Potential mechanisms might include decreased GHB breakdown, increased absorption, and/or increased activity.
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

First, the big picture: GBL isn't a real supplement. Your body quickly turns it into GHB, a strong sedative that's illegal for human use and can cause coma, seizures, and death on its own. If you're looking for help with sleep, anxiety, or substance use, please reach out to a doctor or pharmacist instead.

Now, about combining it with topiramate: there's a case report where adding even a low dose of topiramate roughly doubled GHB blood levels. That patient ended up confused, twitching, with pinpoint pupils, and slipped into a coma. The thinking is that topiramate may slow GHB breakdown or boost its effect. This is anecdotal evidence, but the danger is serious enough that the two should never be mixed. Please talk with your doctor or pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Weiss T, Müller D, Marti I, Happold C, Russmann S. Gamma-hydroxybutyrate (GHB) and topiramate--clinically relevant drug interaction suggested by a case of coma and increased plasma GHB concentration. Eur J Clin Pharmacol. 2013 May;69(5):1193-4. 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

Gamma Butyrolactone (gbl) Also Interacts With Other Medications

Gamma Butyrolactone (gbl) has 270 moderate known drug interactions in our database — the Topiramate one above is among them. If you take anything else, check it against the full list below.

Moderate 270 No known interaction 2,560 (incl. Topiramate)
Taking anything else?

Check Another of Your Medications Against Gamma Butyrolactone (gbl)

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

From our Q&A

Questions About Gamma Butyrolactone (gbl) or Topiramate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Gamma Butyrolactone (gbl) or Topiramate, 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 Topiramate

This page covers Gamma Butyrolactone (gbl) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Topiramate page lists 125 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 · 101 moderate · 17 minor.

From our pharmacist’s overview on the Topiramate page

“Most people taking topiramate (Topamax, Trokendi XR) are managing seizures or preventing migraines, and the drug is famous for causing fog and drowsiness all on its own. That is why this list of 125 supplements deserves real vigilance.”

Reviewed by 2 · Jul 18, 2026

Open the Topiramate interaction page

How much people look this up

Where Gamma Butyrolactone (gbl) and Topiramate 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 Gamma Butyrolactone (gbl)
Steady interest

#1,292 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Topiramate
Top 25%

#554 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 Gamma Butyrolactone (gbl)

What is Gamma Butyrolactone (gbl)?

Gamma Butyrolactone (gbl)
  • Recreational intoxication and euphoria
  • Relaxation and sedation
  • Sleep aid (misused)
  • Bodybuilding/muscle building claims (unproven)
  • Industrial solvent and cleaner

Gamma butyrolactone (GBL) is a toxic industrial solvent, not a dietary supplement, and the body converts it into GHB, a powerful and dangerous sedative. It is illegal to sell or possess for human use in the United States, has no proven medical or supplemental benefit, and can cause coma, seizures, and death. Do not take GBL — if you are seeking help for sleep, anxiety, or substance use, talk to a doctor or pharmacist.

Read the full Gamma Butyrolactone (gbl) monograph & all interactions
Medication

About Topiramate

What Is Topiramate Used For?

Brand names: Topamax, Trokendi XR, Qudexy XR, Eprontia

  • Topiramate is used alone or with other medications to treat certain types of seizures including primary generalized tonic-clonic seizures (formerly known as a grand mal seizure; seizure that involves the entire body) and partial onset seizures (seizures that involve only one part of the brain). Topiramate is also used with other medications to control seizures in people who have Lennox-Gastaut syndrome (a disorder that causes seizures and developmental delays). Topiramate is also used to prevent migraine headaches but not to relieve the pain of migraine headaches when they occur. Topiramate is in a class of medications called anticonvulsants. It works by decreasing abnormal excitement in the brain.

See full Topiramate drug information
Keep checking

Other Drugs & Gamma Butyrolactone (gbl)

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

0Major
270Moderate
0Minor
2,559No known interaction
270 Moderate 2,559 No interaction
Moderate

270 interactions

Showing 60 of 270 moderate interactions — see all 270 on the Gamma Butyrolactone (gbl) page.

No interaction 2,559 drugs checked — show the list

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

Showing the 60 most looked-up of 2,559 medications checked with no known interaction — see the full Gamma Butyrolactone (gbl) list.

See the full Gamma Butyrolactone (gbl) interactions page
See every supplement checked against Topiramate, 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
Gamma Butyrolactone (gbl) monograph › Uses, safety, and every drug interaction in one place Topiramate supplement interactions › Every supplement checked against Topiramate, ranked by severity Topiramate 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 Gamma Butyrolactone (gbl) and Topiramate Together: Common Questions

Can you take Gamma Butyrolactone (gbl) with Topiramate?
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.
Why are there 3 interactions listed for Gamma Butyrolactone (gbl) and Topiramate?
Topiramate belongs to more than one drug category, and Gamma Butyrolactone (gbl) interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Gamma Butyrolactone (gbl) and Topiramate 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 Topiramate and Gamma Butyrolactone (gbl)?

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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.