No reaction
No reactionNot yet reviewed — this article is pending editorial review by Lyrea.
Baclofen
β-(4-chlorophenyl)-GABA
Lioresal, Gablofen, Kemstro, Liofen, Fleqsuvy
Baclofen is a depressant and muscle relaxant of the butyric acid class that acts as a GABA-B receptor agonist.12 Originally synthesized in 1962 to treat epilepsy, it proved ineffective for that purpose but was later approved in 1977 for managing muscle spasticity.31 Chemically related to phenibut, pregabalin, and gabapentin, it produces sedation, anxiety suppression, and moderate euphoria. It has also been researched as a potential treatment for alcohol dependence.42
Dosage & Duration
Dosage
Threshold~5 mg
Light10-20 mg
Moderate20-50 mg
Strong50-75 mg
Heavy75+ mg
Bioavailability
70-85%
Doses exceeding 125 mg carry substantial risk of blackout and respiratory depression. Tolerance to effects builds quickly with repeated administration.
Duration
Onset15-75 minutes
Come Up1-1.5 hours
Peak1-2 hours
Offset1.5-2.5 hours
After Effects6-12 hours
Total8-14 hours
Half-life
2-6 hours
Subjective Effects
The baclofen experience is dominated by muscle relaxation, sedation, and anxiety suppression, with a mild euphoria reported at recreational doses. The overall character is frequently compared to phenibut, a structurally related GABA-B agonist, though baclofen is generally considered less recreational. Sensory alteration is essentially absent; the experience is defined by its depressant body effects and a calm, dulled mental state.
Physical
Pronounced muscle relaxation and a heavy, sedated body feeling are the core physical effects, often accompanied by drowsiness, weakness, and dizziness. Nausea, headaches, and impaired motor coordination can occur, and respiratory depression becomes a serious risk at high doses.
Sedation
Uncomfortable
Cognitive
The headspace is calm and anxiolytic, with reduced anxiety as the most consistently reported mental effect alongside a mild euphoria. At higher doses, concentration and memory become noticeably impaired, and thinking takes on a foggy, sedated quality.
Emotional
Suppressions
Pharmacology
Pharmacodynamics
Baclofen acts as an agonist at the GABA-B receptor, binding to both the B1 and B2 subunits on pre- and post-synaptic neurons.5 Receptor activation causes neuronal hyperpolarization through potassium influx, reducing presynaptic calcium entry and decreasing the release of excitatory neurotransmitters, which inhibits both mono- and polysynaptic reflex transmission at the spinal cord.51 Baclofen also blocks α2δ subunit-containing voltage-gated calcium channels, though with weak affinity (Ki = 156 μM) that is considered likely not clinically relevant. GABA-B receptor activation is additionally thought to reduce dopaminergic activity in the mesolimbic pathway.5
Pharmacokinetics
Baclofen is rapidly absorbed through the gastrointestinal tract following oral administration, with a bioavailability of approximately 70-85%.6 Only about 15% of the oral dose is metabolized in the liver, primarily through deamination.57 The elimination half-life following oral administration ranges from approximately 2 to 6 hours, with longer estimates of approximately 5.6 to 6.8 hours also described.51
Dangerous
Highest riskThese combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.
DissociativesStimulants
Caution
Use cautionThese combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.
1,2-BenzodiazepineAbacavirAcarboseAcebutololAceclofenac
Tolerance
Full Tolerance
Tolerance to sedative-hypnotic effects can appear after only several days of uninterrupted baclofen use.
Cross Tolerance
GABAergic depressants
Baseline Reset
Following cessation, tolerance returns to baseline within 7-14 days.
Harm Potential
Addiction & Dependence
Psychological
ModerateModerate abuse potential with risk of psychological dependence. Compulsive redosing has been reported as an after effect of use.
Physical
HighPhysical dependence develops with chronic use, potentially occurring within weeks of regular dosing at low or high doses. Withdrawal syndrome resembles benzodiazepine and alcohol withdrawal, with symptoms ranging from anxiety, tremors, and insomnia to severe manifestations including hallucinations, delirium, psychosis, seizures, and extreme muscle rigidity resembling neuroleptic malignant syndrome.81 Abrupt discontinuation is not advised; gradual tapering is necessary.1
Toxicity
Central Nervous System
CNS depression including sedation, somnolence, and ataxia occurs at therapeutic and recreational doses; overdose may cause altered mental status, hypothermia, and coma that can mimic brain death.9
Respiratory
Respiratory depression and insufficiency may occur, particularly at higher doses or in overdose; risk increases significantly when combined with other CNS depressants.5
Cardiovascular
Cardiovascular depression is possible at high doses; overdose may cause bradycardia, tachycardia, hypertension, and cardiac conduction abnormalities, though these effects are uncommon.5
Musculoskeletal
Rhabdomyolysis may occur if baclofen use is stopped abruptly after chronic administration; this is a withdrawal complication rather than a direct toxic effect during use.1
Renal
Baclofen should be avoided in chronic kidney disease and end-stage renal disease as even small doses can cause excessive toxicity due to impaired drug clearance; this represents accumulation toxicity rather than direct nephrotoxicity.11
Psychosis Risk
Psychosis, hallucinations (auditory, visual, and tactile), delusions, delirium, confusion, disorientation, and mania may occur during withdrawal from chronic use, particularly with abrupt discontinuation.81 These psychiatric symptoms are associated with the withdrawal syndrome rather than acute intoxication.12
Seizure Risk
Seizures may occur in overdose or with abrupt discontinuation after chronic use.1 Withdrawal-related seizures are a serious concern requiring gradual tapering when discontinuing therapy.5 High-dose combinations with sedatives may also precipitate de novo seizures.
History & Culture
Discovery and Development
Baclofen was first synthesized in 1962 by Swiss chemist Heinrich Keberle at Ciba-Geigy in Basel, Switzerland.13 The compound was designed with the intention of enhancing the lipophilicity of gamma-aminobutyric acid (GABA) to enable penetration of the…
Legality
International
1961 Single Convention: baclofen is not scheduled.
1971 Convention on Psychotropic Substances: baclofen is not scheduled.
1988 Convention: baclofen is not listed in precursor Tables I or II.
By Country
United StatesPrescription onlyRx only
Federal Food, Drug, and Cosmetic Act; current DailyMed labeling23
Current official medicine law and labeling establish baclofen as prescription-only in United States.
FrancePrescription onlyCitation needed
RussiaPrescription onlyCitation needed
Regulated as a prescription medication. Storing or transporting baclofen without a valid prescription may constitute a criminal offense and could result in prosecution.
TurkeyAvailable without prescriptionCitation needed
Can be obtained at pharmacies without requiring a prescription, making it more accessible than in most other countries.
CanadaPrescription onlyPrescription drug
Health Canada Drug Product Database18
Current official medicine records identify baclofen as prescription-only in Canada.
GermanyPrescription onlyPrescription-only medicine
Arzneimittelverschreibungsverordnung, Anlage 120
Current official medicine law and labeling establish baclofen as prescription-only in Germany.
SwedenPrescription onlyCitation needed
Regulated as a prescription medication. Available through pharmacies with a valid prescription from a licensed healthcare provider.21
United KingdomPrescription onlyPrescription Only Medicine
Human Medicines Regulations 2012; current baclofen product authorisation22
Current official medicine records identify baclofen as prescription-only in United Kingdom.
References
Source Pages
Citations
- Ozobax- baclofen solution. DailyMed (n.d.). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=92153f69-bc9b-4bef-9a8e-751effde5c7e#ozobax-baclofen-oral-solution1234567891011
- Caitlin N. Kent, Charlotte Park, & Craig W. Lindsley. (n.d.). Classics in Chemical Neuroscience: Baclofen. ACS Chemical Neuroscience. https://doi.org/10.1021/acschemneuro.0c0025412
- Baclofen therapeutics, toxicity, and withdrawal. AAPS PharmSciTech (n.d.). https://pmc.ncbi.nlm.nih.gov/articles/PMC8182184/1
- Roberta Agabio, Rosella Saulle, Susanne Rösner, & Silvia Minozzi. (January 2023). Baclofen for alcohol use disorder. The Cochrane Database of Systematic Reviews, 1(1). https://doi.org/10.1002/14651858.cd012557.pub31
- Jia W Romito, Emily R Turner, John A Rosener, Landon Coldiron, Ashutosh Udipi, Linsey Nohrn, Jacob Tausiani, & Bryan T Romito. (2021). Baclofen therapeutics, toxicity, and withdrawal: A narrative review. SAGE Open Medicine, 9. https://doi.org/10.1177/2050312121102219712345678
- StatPearls [Internet]. StatPearls Publishing (May 2022). https://pubmed.ncbi.nlm.nih.gov/30252293/1
- KEMSTRO (baclofen orally disintegrating tablets) label. DailyMed (n.d.). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f133fe04-1550-4fa4-9dc4-652c27936bf212
- Bret D. Alvis, & Christopher M. Sobey. (January 2017). Oral Baclofen Withdrawal Resulting in Progressive Weakness and Sedation Requiring Intensive Care Admission. The Neurohospitalist, 7(1), 39–40. https://doi.org/10.1177/194187441663740412
- Lauren Murphy, Hannah Wolfer, & Robert G. Hendrickson. (June 2021). Toxicologic Confounders of Brain Death Determination: A Narrative Review. Neurocritical Care, 34(3), 1072–1089. https://doi.org/10.1007/s12028-020-01114-y1
- Holly E. Perry MD, Robert O. Wright MD, Michael W. Shannon MD, & Alan D. Woolf MD. (June 1998). Baclofen overdose: drug experimentation in a group of adolescents. Pediatrics, 101(6), 1045–1048. https://doi.org/10.1542/peds.101.6.10451
- Amr El-Husseini, Alberto Sabucedo, Jorge Lamarche, Craig Courville, & Alfredo Peguero. (26 October 2011). Baclofen toxicity in patients with advanced nephropathy: proposal for new labeling. American Journal of Nephrology, 34(6), 491–495. https://doi.org/10.1159/0003332471
- Raphael J. Leo, & Daniel Baer. (Nov–Dec 2005). Delirium associated with baclofen withdrawal: a review of common presentations and management strategies. Psychosomatics, 46(6), 503–507. https://doi.org/10.1176/appi.psy.46.6.5031
- Ameisen O. (March-April 2005). Complete and prolonged suppression of symptoms and consequences of alcohol-dependence using high-dose baclofen: a self-case report of a physician. Alcohol and Alcoholism, 40(2), 147-150. https://pubmed.ncbi.nlm.nih.gov/15596425/1
- Baclofen. Chemistry World (n.d.). https://www.chemistryworld.com/podcasts/baclofen/3010770.article12
- Baclofen in alcohol use disorder: An analysis of the data provided by the French 'Temporary Recommendation for Use' 2014–2017 cohort. Drug and Alcohol Dependence Reports (October 2022). https://pmc.ncbi.nlm.nih.gov/articles/PMC9597083/1
- France Grants an Approval to Baclofen for Alcohol Dependence. Alcohol and Alcoholism, 55(1), 44 (January 2020). https://doi.org/10.1093/alcalc/agz07012
- Health Canada Drug Product Database. health-products.canada.ca (n.d.). https://health-products.canada.ca/dpd-bdpp/index-eng.jsp1
- Renaud de Beaurepaire, & Benjamin Rolland. (2022). Baclofen in alcohol use disorder: An analysis of the data provided by the French "Temporary Recommendation for Use" 2014–2017 cohort. Frontiers in Psychiatry. https://doi.org/10.3389/fpsyt.2022.9497501
- Anlage 1 AMVV. (2020). https://www.gesetze-im-internet.de/amvv/anlage_1.html1
- Baclofen Medical Valley 10 mg tabletter – Bipacksedel (Swedish MPA patient information leaflet). Läkemedelsverket (Swedish Medical Products Agency) (n.d.). https://docetp.mpa.se/LMF/Baclofen%20Medical%20Valley%20tablet%20PL_09001bee80e7e67c.pdf1
- Federal Food, Drug, and Cosmetic Act; current DailyMed labeling. dailymed.nlm.nih.gov (n.d.). https://dailymed.nlm.nih.gov/dailymed/search.cfm?query=baclofen1
Automated synthesisInformation aggregated and synthesized using an autonomous workflow built by Josie Kins.
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