Drug & supplement interaction

Gamma Butyrolactone (gbl) + Dextromethorphan

Dextromethorphan brand names: Hold, Benylin Adult, Benylin Pediatric, Theraflu Thin Strips Long Acting Cough, Neo Citran Thin Strips Cough.

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

We found no known interaction between Gamma Butyrolactone (gbl) and Dextromethorphan 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.

Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Gamma Butyrolactone (gbl) and Dextromethorphan

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 Dextromethorphan and Gamma Butyrolactone (gbl) 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.

Gamma Butyrolactone (gbl) safety at a glance

Gamma Butyrolacton... overall Avoid GBL is a toxic, illegal substance that can cause coma and death; it should never be consumed.
Pregnancy Unsafe When used orally; avoid using. Read the full pregnancy detail
Breastfeeding Unsafe When used orally; avoid using. 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 Dextromethorphan and Gamma Butyrolactone (gbl)? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Dextromethorphan

Interactions in our licensed database are recorded against drug classes, not just single drug names. Dextromethorphan is filed under 6 classifications — including serotonergic drugs, serotonergic drugs, cytochrome p450 2d6 (cyp2d6) substrates. Gamma Butyrolactone (gbl) has documented interactions with 10 drug classes — the most serious being alcohol (ethanol) (moderate), amphetamines (moderate) and anticonvulsants (moderate) — and none of Dextromethorphan’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

Gamma Butyrolactone (gbl) Does Interact With Other Medications

Gamma Butyrolactone (gbl) has 271 moderate known drug interactions in our database — Dextromethorphan isn’t one of them. If you take anything else, check it against the full list below.

Moderate 271 No known interaction 2,559 (incl. Dextromethorphan)
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.

What to actually watch for

What Gamma Butyrolactone (gbl) Itself Has Been Linked To

This is not an interaction — nothing below involves Dextromethorphan. It is the side-effect record for Gamma Butyrolactone (gbl) on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Gamma Butyrolactone (gbl), this list is the first place to look. 8 entries are worth acting on rather than waiting out — marked below.

  • Dependence or withdrawal symptoms Worth acting on Additional detail

    “Orally, GBL can cause mental changes, such as agitation, combativeness, and amnesia.

    Withdrawal symptoms have been reported in people who ingest diluted products containing almost pure GBL every few hours. Withdrawal symptoms can start within 2-72 hours and can last up to 15 days.”

    Gamma Butyrolactone (gbl) · Natural Medicines adverse-effect record, reported in anxiety.

    6 sources cited
    1. 665. LoVecchio F, Curry SC, Bagnasco T. Butyrolactone-induced central nervous system depression after ingestion of RenewTrient, a dietary supplement. N Engl J Med 1998;339:847-8.
    2. 682. FDA. FDA warns about products containing gamma butyrolactone or GBL and asks companies to issue a recall. Talk Paper, 21 January 1999.
    3. 1430. Anon. Adverse events associated with ingestion of gamma-butyrolactone--Minnesota, New Mexico, and Texas, 1998-1999. MMWR Morb Mortal Wkly Rep 1999;48:137-40.
    4. 95118. Bhattacharya IS, Watson F, Bruce M. A case of ?-butyrolactone associated with severe withdrawal delirium and acute renal failure. Eur Addict Res 2011;17(4):169-71. PubMed
    5. 95129. Eiden C, Capdevielle D, Deddouche C, et al. Neuroleptic malignant syndrome-like reaction precipitated by antipsychotics in a patient with gamma-butyrolactone withdrawal. J Addict Med 2011;5(4):302-3. PubMed
    6. 10375. Schneir AB, Ly BT, Clark RF. A case of withdrawal from the GHB precursors gamma-butyrolactone and 1,4-butanediol. J Emerg Med 2001;21:31-3.. PubMed

    “Orally, GBL can cause bradycardia, hypotension, tachycardia, and cardiac arrest.

    Consistent use of GBL followed by abrupt discontinuation is associated with withdrawal symptoms, including tachycardia and hypertension.”

    Gamma Butyrolactone (gbl) · Natural Medicines adverse-effect record, reported in cardiac arrest.

    6 sources cited
    1. 665. LoVecchio F, Curry SC, Bagnasco T. Butyrolactone-induced central nervous system depression after ingestion of RenewTrient, a dietary supplement. N Engl J Med 1998;339:847-8.
    2. 682. FDA. FDA warns about products containing gamma butyrolactone or GBL and asks companies to issue a recall. Talk Paper, 21 January 1999.
    3. 1430. Anon. Adverse events associated with ingestion of gamma-butyrolactone--Minnesota, New Mexico, and Texas, 1998-1999. MMWR Morb Mortal Wkly Rep 1999;48:137-40.
    4. 95127. Corkery JM, Loi B, Claridge H, et al. Gamma hydroxybutyrate (GHB), gamma butyrolactone (GBL) and 1,4-butanediol (1,4-BD; BDO): A literature review with a focus on UK fatalities related to non-medical use. Neurosci Biobehav Rev 2015;53:52-78. PubMed
    5. 95128. Dargan PI, Button J, Davies S, et al. The first reported UK fatality related to gamma-butyrolactone (GBL) ingestion. J R Soc Med 2009;102(12):546-7.
    6. 95130. Heytens L, Neels H, Van Regenmortel N, et al. Near-fatal persistent anion- and osmolal-gap acidosis due to massive gamma-butyrolactone/ethanol intoxication. Ann Clin Biochem 2015;52(Pt 2):283-7. PubMed
  • Severe muscle breakdown Worth acting on Additional detail

    “Orally, GBL can cause involuntary muscle movements. Rarely, it has been reported to cause rhabdomyolysis.”

    Gamma Butyrolactone (gbl) · Natural Medicines adverse-effect record, reported in muscle breakdown.

    4 sources cited
    1. 665. LoVecchio F, Curry SC, Bagnasco T. Butyrolactone-induced central nervous system depression after ingestion of RenewTrient, a dietary supplement. N Engl J Med 1998;339:847-8.
    2. 682. FDA. FDA warns about products containing gamma butyrolactone or GBL and asks companies to issue a recall. Talk Paper, 21 January 1999.
    3. 1430. Anon. Adverse events associated with ingestion of gamma-butyrolactone--Minnesota, New Mexico, and Texas, 1998-1999. MMWR Morb Mortal Wkly Rep 1999;48:137-40.
    4. 95118. Bhattacharya IS, Watson F, Bruce M. A case of ?-butyrolactone associated with severe withdrawal delirium and acute renal failure. Eur Addict Res 2011;17(4):169-71. PubMed
  • Memory problems / Hallucinations / Confusion Worth acting on Additional detail

    “GBL is generally considered unsafe for any use. Any benefits do not outweigh the risks of toxicity.

    Most Common Adverse Effects:

    Orally: Agitation, amnesia, anxiety, bradycardia, confusion, hallucinations, hypotension, nausea, tachycardia, tremor, vomiting.

    Serious Adverse Effects (Rare):

    Orally: Cardiac arrest, coma, death, pulmonary edema, respiratory depression, seizures, withdrawal.”

    Gamma Butyrolactone (gbl) · Natural Medicines adverse-effect record, reported in anxiety.

  • A slow heartbeat Worth acting on Additional detail

    Recorded for Gamma Butyrolactone (gbl) in the same Natural Medicines adverse-effect record shown under Memory problems / Hallucinations / Confusion above.

  • Fainting Worth acting on Additional detail

    “Orally, GBL can cause fainting, seizures, and severe central nervous system depression. In many cases, unconsciousness or coma have been reported.

    Withdrawal symptoms have been reported in people who ingest diluted products containing almost pure GBL every few hours. Withdrawal symptoms can start within 2-72 hours and can last for up to 15 days.”

    Gamma Butyrolactone (gbl) · Natural Medicines adverse-effect record, reported in depression.

    6 sources cited
    1. 665. LoVecchio F, Curry SC, Bagnasco T. Butyrolactone-induced central nervous system depression after ingestion of RenewTrient, a dietary supplement. N Engl J Med 1998;339:847-8.
    2. 682. FDA. FDA warns about products containing gamma butyrolactone or GBL and asks companies to issue a recall. Talk Paper, 21 January 1999.
    3. 1430. Anon. Adverse events associated with ingestion of gamma-butyrolactone--Minnesota, New Mexico, and Texas, 1998-1999. MMWR Morb Mortal Wkly Rep 1999;48:137-40.
    4. 93819. Bosch OG, Eisenegger C, Gertsch J, et al. Gamma-hydroxybutyrate enhances mood and prosocial behavior without affecting plasma oxytocin and testosterone. Psychoneuroendocrinology. 2015 Dec;62:1-10. PubMed
    5. 95127. Corkery JM, Loi B, Claridge H, et al. Gamma hydroxybutyrate (GHB), gamma butyrolactone (GBL) and 1,4-butanediol (1,4-BD; BDO): A literature review with a focus on UK fatalities related to non-medical use. Neurosci Biobehav Rev 2015;53:52-78. PubMed
    6. 95129. Eiden C, Capdevielle D, Deddouche C, et al. Neuroleptic malignant syndrome-like reaction precipitated by antipsychotics in a patient with gamma-butyrolactone withdrawal. J Addict Med 2011;5(4):302-3. PubMed
  • Seizures Worth acting on Additional detail

    Recorded for Gamma Butyrolactone (gbl) in the same Natural Medicines adverse-effect record shown under Memory problems / Hallucinations / Confusion above.

  • Kidney problems Worth acting on Additional detail

    “Orally, GBL has been reported to cause acute kidney injury, including changes in serum creatinine levels. There is one case report of a 24-year-old male developing acute kidney failure during withdrawal from GBL obtained from varnish remover. The renal toxicity in this patient was possibly exacerbated by other ingredients in the varnish remover, including propylene glycol.”

    Gamma Butyrolactone (gbl) · Natural Medicines adverse-effect record, reported in kidney failure.

    4 sources cited
    1. 95118. Bhattacharya IS, Watson F, Bruce M. A case of ?-butyrolactone associated with severe withdrawal delirium and acute renal failure. Eur Addict Res 2011;17(4):169-71. PubMed
    2. 95131. Roberts DM, Smith MW, Gopalakrishnan M, et al. Extreme ?-butyrolactone overdose with severe metabolic acidosis requiring hemodialysis. Ann Emerg Med 2011;58(1):83-5. PubMed
    3. 105714. van Helmond LPFM, Gresnigt FMJ. Safety of withholding intubation in gamma-hydroxybutyrate- and gamma-butyrolactone-intoxicated coma patients in the emergency department. Eur J Emerg Med. 2020 Jun;27(3):223-227. PubMed
    4. 105715. Delcourt N, Lanot T, Vardon-Bounes F, Gandia P, Franchitto N. Severe metabolic failures after recreational ingestion of ?-butyrolactone. J Clin Psychopharmacol. 2020 Nov/Dec;40(6):624-626. PubMed
  • Raised blood pressure Worth acting on Additional detail

    Recorded for Gamma Butyrolactone (gbl) in the same Natural Medicines adverse-effect record shown under Dependence or withdrawal symptoms above.

Showing the 10 most notable of 21 recorded effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

Everything above comes from the Natural Medicines adverse-effect record for Gamma Butyrolactone (gbl) — expand a row for the licensed statement it rests on. We haven’t matched Dextromethorphan to its FDA label in our system yet, so we can’t compare its own side-effect list here — the leaflet that comes with your prescription is the authoritative list for Dextromethorphan.

Special populations

Gamma Butyrolactone (gbl) in Pregnancy & Breastfeeding

Pregnancy And Lactation Unsafe

When used orally; 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 Gamma Butyrolactone (gbl) or Dextromethorphan

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 Dextromethorphan, 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 Dextromethorphan

This page covers Gamma Butyrolactone (gbl) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Dextromethorphan page lists 171 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), Lithium (major), St. John's Wort (major) and 1,3-dmaa (moderate).

By severity: 4 major · 125 moderate · 42 minor.

From our pharmacist’s overview on the Dextromethorphan page

“A glass of grapefruit juice can push dextromethorphan (Benylin, Hold, and other cough medicines) to higher levels than intended, one of four major-rated entries among the 171 supplements and herbs on file, and the list as a whole warrants real care. Most interactions trace back to the liver enzymes (CYP3A4 and CYP2D6) that clear dextro…”

Reviewed by 2 · Jul 18, 2026

Open the Dextromethorphan interaction page

How much people look this up

Where Gamma Butyrolactone (gbl) and Dextromethorphan 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

#1,208 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Dextromethorphan
Top 5%

#80 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 Gamma Butyrolactone (gbl) reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Gamma Butyrolactone (gbl) and Dextromethorphan records this page draws on were last updated July 10, 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 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.

Not applicable (synthetic industrial chemical) · Liquid (illicitly sold); used industrially as a solvent

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

Gamma Butyrolactone (gbl): dosing

There is no safe or recommended dose of GBL. It is not a supplement, it is illegal to sell for human use, and any amount can be dangerous because it converts into the potent sedative GHB.No pharmacist or doctor should recommend taking GBL.

From our Gamma Butyrolactone (gbl) monograph — the full record covers uses, side effects and every documented interaction.

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

About Dextromethorphan

What Is Dextromethorphan Used For?

Brand names: Hold, Benylin Adult, Benylin Pediatric, Theraflu Thin Strips Long Acting Cough, Neo Citran Thin Strips Cough

Dextromethorphan temporarily relieves cough due to minor throat and bronchial irritation, such as the kind that comes with the common cold or breathing in irritants. It also helps reduce the urge to cough so you — or your child — can get to sleep.

Some products, including CVS Long Acting Cough and Premier Value Tussin Cough oral liquids, are also indicated to help loosen phlegm (mucus) and thin bronchial secretions to help drain the airways.

See full Dextromethorphan 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
271Moderate
0Minor
2,558No known interaction
271 Moderate 2,558 No interaction
Moderate

271 interactions

Showing 60 of 271 moderate interactions — see all 271 on the Gamma Butyrolactone (gbl) page.

No interaction 2,558 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 2,558 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 Dextromethorphan, ranked by severity
Evidence & sources

Gamma Butyrolactone (gbl) References

The 28 references that drive our Gamma Butyrolactone (gbl) 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. Soderling E, Le Bell A, Kirstila V, Tenovuo J. Betaine-containing toothpaste relieves subjective symptoms of dry mouth. Acta Odontol Scand 1998;56:65-9.
  2. LoVecchio F, Curry SC, Bagnasco T. Butyrolactone-induced central nervous system depression after ingestion of RenewTrient, a dietary supplement. N Engl J Med 1998;339:847-8.
  3. FDA. FDA warns about products containing gamma butyrolactone or GBL and asks companies to issue a recall. Talk Paper, 21 January 1999.
  4. Anon. Adverse events associated with ingestion of gamma-butyrolactone--Minnesota, New Mexico, and Texas, 1998-1999. MMWR Morb Mortal Wkly Rep 1999;48:137-40.
  5. Harrington RD, Woodward JA, Hooton TM, et al. Life-threatening interactions between HIV-1 protease inhibitors and the illicit drugs MDMA and gamma-hydroxybutyrate. Arch Intern Med 1999;159:2221-4.
  6. Anon. FDA alert on misuse of consumer products containing GHB, GBL and BD. Food and Drug Administration, Rockville, MD. June 15, 1999.
  7. 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
  8. Anon. Multistate outbreak of poisonings associated with illicit use of gamma hydroxy butyrate. JAMA 1991;265:447-8. DOI
  9. Carotenuto A, De Feo V, Fattorusso E, et al. The flavonoids of Allium ursinum. Phytochem 1996;41:531-6. PubMed
  10. FDA Talk Paper. FDA Warns About GBL-Related Products. 1999. Available at: vm.cfsan.fda.gov/~lrd/tpgbl2.html
  11. Ferrara SD, Tedeschi L, Frison G, Rossi A. Fatality due to gamma-hydroxybutyric acid (GHB) and heroin intoxication. J Forensic Sci 1995;40:501-4. DOI
  12. Schneir AB, Ly BT, Clark RF. A case of withdrawal from the GHB precursors gamma-butyrolactone and 1,4-butanediol. J Emerg Med 2001;21:31-3.. PubMed
  13. Sivilotti ML, Burns MJ, Aaron CK, Greenberg MJ. Pentobarbital for severe gamma-butyrolactone withdrawal. Ann Emerg Med 2001;38:660-5.. PubMed
  14. Bosch OG, Eisenegger C, Gertsch J, et al. Gamma-hydroxybutyrate enhances mood and prosocial behavior without affecting plasma oxytocin and testosterone. Psychoneuroendocrinology. 2015 Dec;62:1-10. PubMed
  15. Thai D, Dyer JE, Benowitz NL, Haller CA. Gamma-hydroxybutyrate and ethanol effects and interactions in humans. J Clin Psychopharmacol. 2006 Oct;26(5):524-9. PubMed

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 Gamma Butyrolactone (gbl) and Dextromethorphan Together: Common Questions

Is it safe to take Gamma Butyrolactone (gbl) with Dextromethorphan?
We do not list a known interaction between Gamma Butyrolactone (gbl) and Dextromethorphan. 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 Gamma Butyrolactone (gbl) and Dextromethorphan combination checked?
Interactions in our licensed database are recorded against drug classes. Dextromethorphan is filed under 6 classifications, and Gamma Butyrolactone (gbl) has documented interactions with 10 drug classes — none of Dextromethorphan'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 Gamma Butyrolactone (gbl) interact with any other medications?
Yes. Gamma Butyrolactone (gbl) has 271 documented drug interactions in our database — Dextromethorphan 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 Dextromethorphan interact with any supplements?
Yes. Dextromethorphan has documented interactions with 171 supplements in our database — Gamma Butyrolactone (gbl) is not one of them. The Dextromethorphan 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

Gamma Butyrolactone (gbl) monograph Uses, safety profile, and every drug interaction in one place Dextromethorphan drug information The full plain-English guide to this medication Dextromethorphan supplement interactions Every supplement checked against Dextromethorphan, 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 28 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Dextromethorphan and Gamma Butyrolactone (gbl)?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.