What is Fletazepam?


Fletazepam is a drug which is a benzodiazepine derivative. It has sedative and anxiolytic effects similar to those produced by other benzodiazepine derivatives, but is mainly notable for its strong muscle relaxant properties.

Fletazepam is most closely related to other N-trifluoroethyl substituted benzodiazepines such as halazepam and quazepam.

What is Halazepam?


Halazepam is a benzodiazepine derivative that was marketed under the brand names Paxipam in the United States, Alapryl in Spain, and Pacinone in Portugal.

Medical Uses

Halazepam was used for the treatment of anxiety.

Adverse Effects

Adverse effects include drowsiness, confusion, dizziness, and sedation. Gastrointestinal side effects have also been reported including dry mouth and nausea.

Pharmacokinetics and Pharmacodynamics

Pharmacokinetics and pharmacodynamics were listed in Current Psychotherapeutic Drugs published on 15 June 1998 as follows:

  • Onset of action: Intermediate to slow.
  • Plasma half life: 14 hours for parent drug and 30-100 hours for its metabolite.
  • Peak plasma levels: 1-3 hours for parent drug and 3-6 hours for its metabolite.
  • Metabolism: Metabolised into desmethyldiazepam and 3-hydroxyhalazepam (in the liver).
  • Excretion: Excreted through kidneys.
  • Protein binding: 98% bound to plasma protein.

Regulatory Information

Halazepam is classified as a schedule 4 controlled substance with a corresponding code 2762 by the Drug Enforcement Administration (DEA).

Commercial Production

Halazepam was invented by Schlesinger Walter in the US. It was marketed as an anti-anxiety agent in 1981. However, Halazepam is not commercially available in the United States because it was withdrawn by its manufacturer for poor sales.