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Baclofen Facts

Depressant; Substituted phenethylamine; GABA-B receptor agonist

Description

Baclofen is a synthetic depressant of the GABA structural analog class.[1] It activates GABA receptors, quieting nerve activity and producing muscle relaxation and sedation.[2]

Subjective effects include muscle relaxation, sedation, reduced anxiety, and cognitive slowing.[3] The experience is defined by a flat, clean calm — tension dissolves without the warmth or euphoria of alcohol or benzodiazepines.

Baclofen produces physical dependence with regular use,[4] and overdose can cause respiratory failure and fixed pupils that mimic brain death.[5][6] Kidney function is the key variable — the drug exits unchanged through the kidneys,[7] so impaired kidneys allow dangerous accumulation.

Dose and durationby route · individual sensitivity varies

Oral(mg)
Threshold< 5 mgLight10 – 20 mgCommon20 – 50 mgStrong50 – 100 mgHeavy100+ mg

Starts in 30 – 75 minLasts 8 – 14 hoursAfter-effects 6 – 12 hours

Body and dependence

Acute toxicity
High
Chronic toxicity
Low
Physical dependence
Moderate
Psychological dependence
Low
Withdrawal
Life-threatening · fatal · medical supervision
Compulsive redosing
Low

Tolerance

Builds
Rapid
Fully resets after
10.5 days
Carries over to
GHB; GBL; phenibut; other GABA-B active agents

Effectslikely at a common dose

Perception
none likely · 2 possible, including Vestibular distortion, Spatial disorientation
Body
Muscle relaxation; Sedation; +10 possible, including Dizziness, Motor control impairment, Nausea
Thinking
none likely · 7 possible, including Cognitive impairment, Decision impairment, Confusion
Feeling
none likely · 3 possible
Self
none likely · 3 possible

Who shouldn't take it

Absolute
Severe renal impairment (eGFR <30); Alcohol; GHB; GBL; Opioids; Methaqualone
Relative
Sleep-disordered breathing; Seizure disorder; Psychiatric instability (active depression/suicidality); Moderate renal impairment; Pregnancy; Benzodiazepines

Combinations62 recorded

Lethal (4)
Alcohol; GHB, GBL; Methaqualone; Opioids
Dangerous (36)
Alpha-2 adrenergic receptor antagonist; Antihistamines; Antipsychotics; Benzodiazepines; Benzodiazepines, Barbiturates; Buprenorphine, Kratom; Cannabis, THC; Clonidine, Guanfacine; MDMA, Amphetamines; Stimulants; Synthetic cannabinoids; Amphetamines; Anticholinergics; Atypical antipsychotics; Buspirone; Caffeine; Cannabis; Dopamine agonists; DXM; Gabapentin, Pregabalin; Ibogaine; Ketamine, DXM, PCP; Lithium; Local anesthetics; and 12 more, see full page
Caution (13)
See full page: psychedex.org/substances/baclofen
Not graded (9)
Not listed never means safe.

Seek help immediately if

  • Extreme drowsiness — can't stay awake or be roused
  • Confusion, slurred speech, severe loss of coordination
  • Slow, shallow, or irregular breathing
  • Unconsciousness / unresponsive; limp, floppy body
  • Blue lips or fingertips
  • Vomiting while sedated (choking / aspiration risk)
  • Cold, clammy skin; weak pulse

What to do

  1. Try to wake them — shout, firm sternal rub
  2. If unresponsive or breathing is impaired, call emergency services
  3. Place them in the recovery position — critical, they can choke on vomit
  4. Monitor breathing continuously; be ready to give rescue breaths / CPR
  5. Never leave them alone to "sleep it off"
  6. Do not give other drugs, stimulants, or more depressants

Most depressant overdoses resolve with airway protection, breathing support, and monitoring. The danger is respiratory depression and choking on vomit — sharply worse when combined with opioids or alcohol. GHB/GBL overdoses often involve sudden deep unconsciousness and may self-resolve, but airway protection is essential.

988 Suicide & Crisis LifelineFireside Project: 62-FIRESIDE

Version r1 · Not medical advice

References

  1. [1]
    ^Kent CN, Park C, Lindsley CW (2020) Classics in Chemical Neuroscience: Baclofen — ACS Chemical Neuroscience doi:10.1021/acschemneuro.0c00254
  2. [2]
    ^Shaye H, Ishchenko A, Lam JH, et al. (2020) Structural basis of the activation of a metabotropic GABA receptor — Nature doi:10.1038/s41586-020-2408-4
  3. [3]
    ^Liu J, Wang LN (2019) Baclofen for alcohol withdrawal — Cochrane Database of Systematic Reviews PMID:31689723
  4. [4]
    ^Iqbal M, Modi P, Sehgal K, et al. (2026) Clinical Presentations and Treatment of Baclofen Toxicity and Withdrawal: A Systematic Review — CNS Drugs PMID:41555041
  5. [5]
    ^Zari Meidani F, Rahmati R, Ghorbankhani M, et al. (2023) Pneumomediastinum: A case report of baclofen toxicity — International Journal of Surgery Case Reports PMID:37801962
  6. [6]
    ^Koker A, Arslan G, Ozden O, et al. (2020) An intoxication mimicking brain death: baclofen — Acta Neurologica Belgica PMID:30196372
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