Multiple-dose quazepam kinetics.
Quazepam, a benzodiazepine hypnotic, was studied in normal subjects to evaluate steady-state kinetics of quazepam and of its major active plasma metabolites, 2-oxoquazepam and N-desalkyl-2-oxoquazepam, after 15 mg once daily by mouth for 14 days. The kinetics of quazepam and 2-oxoquazepam can be best described by a two-compartment open model with first-order absorption/formation kinetics. Quazepam was rapidly absorbed and its two major plasma metabolites appeared very quickly in systemic circulation. The elimination t 1/2s of quazepam, 2-oxoquazepam, and N-desalkyl-2-oxoquazepam were 41, 43, and 75 hr. Steady-state levels were predictable from the kinetic data and were reached by the seventh dose for quazepam and 2-oxoquazepam and by the thirteenth dose for N-desalkyl-2-oxoquazepam. These kinetic profiles may explain the clinical hypnotic effect of quazepam--rapid induction of sleep and long duration of clinical action without appreciable rebound insomnia.
D000042:Absorption; D000284:Administration, Oral; D000328:Adult; D014151:Anti-Anxiety Agents; D001569:Benzodiazepines / Q000378:metabolism*; D001570:Benzodiazepinones / Q000097:blood; D005479:Flurazepam / Q000031:analogs & derivatives / Q000097:blood; D006801:Humans; D007700:Kinetics; D008297:Male
D014151:Anti-Anxiety Agents; D001570:Benzodiazepinones; D001569:Benzodiazepines; C039103:2-oxoquazepam; D005479:Flurazepam; C025130:quazepam; C020965:norflutoprazepam