Drug & supplement interaction

Gamma Butyrolactone (gbl) + Cenobamate

Cenobamate brand name: Xcopri.

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

Cenobamate falls into 2 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
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Gamma Butyrolactone (gbl) and Cenobamate

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Gamma Butyrolactone (gbl) interacts with whole categories of medication. Cenobamate falls into 2 of those categories, so it can interact with Gamma Butyrolactone (gbl) in 2 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 2

Why this applies to Cenobamate

Cenobamate 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

First, an important safety note: GBL isn't a real supplement. It's a toxic solvent your body turns into GHB, a strong sedative that can cause coma, seizures, and death on its own. Please don't take it. If you're struggling with sleep, anxiety, or substance use, reach out to a doctor or pharmacist.

Putting it together with cenobamate (Xcopri) is doubly risky. Cenobamate already slows brain activity and commonly causes drowsiness, dizziness, trouble with balance, and tiredness. GHB piles on top of that, and the big worry is combined sedation and slowed breathing. The evidence here is anecdotal and partly theoretical, but the danger is real enough that the two simply should not be mixed. If you have questions about your seizure medicine, talk with your pharmacist or doctor.

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 2

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

Pairing it with cenobamate (Xcopri) is a real concern. Cenobamate already slows brain activity and can make you drowsy or dizzy. Stacking GHB's sedation on top could deepen that into dangerous slowed breathing or loss of consciousness. To make matters worse, GHB itself can trigger seizures, which may work against the very protection cenobamate is giving you. This warning is theoretical and based on weak, anecdotal evidence, but the stakes here are far too high to risk it.

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.

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 Cenobamate 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. Cenobamate)
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.

Everything else you take

See Every Supplement That Interacts With Cenobamate

This page covers Gamma Butyrolactone (gbl) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Cenobamate page lists 122 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 · 99 moderate · 16 minor.

From our pharmacist’s overview on the Cenobamate page

“Anyone taking cenobamate (Xcopri) for seizures already knows the drug can cause drowsiness on its own, which is exactly why this list warrants genuine vigilance before adding a supplement. Of the 122 ingredients with an interaction on file, seven rate major, and the pattern is lopsided: 78 are sedating in their own right, from kava dow…”

Reviewed by 2 · Jul 18, 2026

Open the Cenobamate interaction page

How much people look this up

Where Gamma Butyrolactone (gbl) and Cenobamate 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

#1,358 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Cenobamate
Top half

#1,121 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 Cenobamate

What Is Cenobamate Used For?

Brand name: Xcopri

Xcopri (cenobamate) tablets are approved to treat partial-onset seizures — a type of epileptic seizure that starts in one area of the brain — in adult patients. It can be used alone or alongside other seizure medications.

See full Cenobamate 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 Cenobamate, 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 Cenobamate supplement interactions › Every supplement checked against Cenobamate, ranked by severity Cenobamate 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 Cenobamate Together: Common Questions

Can you take Gamma Butyrolactone (gbl) with Cenobamate?
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 2 interactions listed for Gamma Butyrolactone (gbl) and Cenobamate?
Cenobamate 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 Cenobamate 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

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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.