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Flubromazepam Facts

Depressant; Anxiolytic; Benzodiazepine; GABA-A receptor positive allosteric modulator

Description

Flubromazepam is a synthetic depressant of the benzodiazepine class. It amplifies the brain's primary inhibitory signaling system, producing sedation, anxiety relief, and muscle relaxation.

Subjective effects include anxiety suppression, heavy sedation, muscle relaxation, amnesia, and disinhibition. The experience is unremarkable in character — a gradual dampening of tension that deepens into sedation — but is defined by extraordinary persistence, with impairment lasting days after a single dose.

Flubromazepam produces physical dependence, and abrupt cessation can cause life-threatening seizures; all documented deaths involve combinations with opioids or other depressants.[1][2][3] The extreme half-life causes silent accumulation — users may not realize they are still intoxicated and redose, which is the primary acute danger.

Dose and durationby route · individual sensitivity varies

Oral(mg)
Threshold< 2 mgLight3 – 5 mgCommon5 – 8 mgStrong8 – 12 mgHeavy12+ mg

Starts in 40 – 90 minLasts 6 – 12 hoursAfter-effects 12 – 72 hours

Body and dependence

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

Tolerance

Builds
Rapid
Fully resets after
10.5 days
Carries over to
benzodiazepines; alcohol; barbiturates; other GABAergic CNS depressants

Effectslikely at a common dose

Perception
Dreaming suppression; +4 possible, including Spatial disorientation, Visual acuity suppression, Vestibular distortion
Body
Sedation; Muscle relaxation; Motor control impairment; Physical fatigue; +10 possible, including Dizziness, Nystagmus (eye wobbles), Headache
Thinking
Memory suppression; Thought deceleration; Cognitive impairment; +14 possible, including Analysis suppression, Delusions of sobriety, Decision impairment
Feeling
Anxiety suppression; +6 possible, including Anhedonia, Depression, Emotional lability
Self
none likely · 7 possible, including Communication suppression, Craving
Time
none likely · 2 possible, including Temporal disorientation

Who shouldn't take it

Absolute
Concurrent opioid use; Concurrent alcohol use; Other CNS depressants (barbiturates, GHB, gabapentinoids)
Relative
Respiratory compromise or obstructive sleep apnea; Myasthenia gravis; History of substance use disorder; Hepatic impairment; Pregnancy; Elderly patients; Acute narrow-angle glaucoma

Combinations60 recorded

Lethal (1)
Opioids
Dangerous (21)
Alpha-2 adrenergic receptor antagonist; Antipsychotics; Atypical antipsychotics; Benzodiazepines; Buprenorphine, Kratom; Cannabis, THC; Clonidine, Guanfacine; Gabapentin, Pregabalin; GHB, Baclofen; GHB, GBL; Local anesthetics; Naltrexone; SNRIs; Stimulants; Synthetic cannabinoids; Ibogaine; Ketamine, DXM, PCP; MAOIs; NSAIDs; Poppers (Alkyl nitrites); Poppers, Nitrates
Caution (26)
See full page: psychedex.org/substances/flubromazepam
Not graded (12)
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]
    ^Butler M, Pirkle J, Carmichael A, Carlson-Dexter P, Rosella T (2025) Successful symptom-based management of active withdrawal from multiple illicit benzodiazepines — BMJ Case Reports doi:10.1136/bcr-2025-266077
  2. [2]
    ^Giorgetti A, Große Perdekamp M, Franchetti G, Pircher R, Pollak S, Pelotti S, Auwärter V (2024) Intoxications involving methoxyacetylfentanyl and U-47700: a study of 3 polydrug fatalities — International Journal of Legal Medicine doi:10.1007/s00414-024-03263-7
  3. [3]
    ^Partridge E, Trobbiani S, Stockham P, Charlwood C, Kostakis C (2018) A Case Study Involving U-47700, Diclazepam and Flubromazepam-Application of Retrospective Analysis of HRMS Data — Journal of Analytical Toxicology doi:10.1093/jat/bky039
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