Halazepam is a trifluoromethyl derivative of nordazepam (desmethyldiazepam) with anxiolytic, anticonvulsant, sedative, and muscle relaxant properties. It is metabolized into pharmacologically active desmethyldiazepam with a half-life of 30-100 hours, contributing to prolonged effects and accumulation with repeated use. Halazepam was marketed as having lower toxicity and less tendency to cause paradoxical hostility than diazepam, though it was withdrawn from the US market in 2009 due to poor sales. Like all benzodiazepines, it carries significant risks of dependence, cognitive impairment, and dangerous interactions with other depressants. Abrupt discontinuation after prolonged use can cause life-threatening withdrawal seizures.
Halazepam molecular structure diagram from the DrugsPRO substance library.
Also known as: Paxipam, Alapryl, Pacinone, SCH-12041
Classification
Chemical: Benzodiazepine
Psychoactive: Depressant
Tag: Anxiolytic
Tag: GABAergic
Tag: Habit-Forming
Tag: Muscle Relaxant
Tag: Sedative
Effects
Sedation
Muscle Relaxation
Physical Euphoria
Respiratory Depression
Anxiolytic
Sedative
Anxiety Suppression
Motor Control Loss
Thought Deceleration
Emotion Suppression
Memory Suppression
Amnesia
Disinhibition
Dulled Perception
Routes of Administration
Oral
Dosage
Light: 10-20 mg
Common: 20-40 mg
Strong: 40-80 mg
Heavy: 3 600 mg (not recommended; markedly increases risk of oversedation, amnesia, and respiratory depression when combined with other depressants)
Threshold: 5 mg (approximate; based on equivalence to ~2.5 mg diazepam)
Duration
Onset: 0.5-1 h
Comeup: 1-2 h
Peak: 1-3 h
Offset: 6-12 h
After Effects: 24-48 h
Total Duration: 6-12 h
Harm Reduction
Check interactions before mixing substances, pay attention to dose spacing and hydration, and treat all dosage guidance as approximate rather than guaranteed safe.
Sources
Substance data is aggregated from the following public harm-reduction and reference sources.
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Halazepam - DrugsPRO vodič za tvari
Halazepam: Halazepam is a trifluoromethyl derivative of nordazepam (desmethyldiazepam) with anxiolytic, anticonvulsant, sedative, and muscle relaxant properties. It is metabolized into pharmacologically active desmethyldiazepam with a half-life of 30-100 hours, contributing to prolonged effects and
