Clobazam: a review of its pharmacological properties and therapeutic use in anxiety.

Clobazam1 is a 1,5-benzodiazepine with antianxiety and anticonvulsant properties, advocated for the treatment of primary anxiety and that associated with organic or functional disorders. Clobazam itself has a half-life of 18 hours, but that of the principal metabolite, N-desmethylclobazam, is about 50 hours. Although the metabolite is pharmacologically less active than the parent drug, steady-state plasma concentrations of the metabolite are 8 times higher than those of the unchanged drug. Therapeutic trials indicate that the antianxiety effect of clobazam 30 to 80 mg daily is comparable with that of half its dose of diazepam. Clobazam has minimal muscle relaxant and hypnotic activity. Although subjective drowsiness has occurred with similar frequency with clobazam and diazepam in some studies, clobazam causes less objectively measured sedation or psychomotor impairment in experimental studies. Results of studies of vigilance and psychomotor performance during therapeutic use in patients are less conclusive, but clobazam may be useful in anxious patients who experience such impairment with other benzodiazepines.