Pharmacokinetics of N-desmethyldiazepam after a single oral dose of clorazepate: the effect of smoking.
The pharmacokinetics of N-desmethyldiazepam was evaluated after oral administration of clorazepate 20 mg to 12 healthy male volunteers (6 smokers; 6 non-smokers), aged 23-29 years. Plasma levels of desmethyldiazepam were measured by gas liquid chromatography. The half life of elimination (t1/2 beta) was significantly longer in the non-smoking volunteers than in the smokers: 54.7 +17.7 versus 29.8 +9.9 h (p less than 0.05). Peak plasma concentrations (Cmax) were higher in non-smokers than in smokers, 413 +106 micrograms/l and 245 +50 micrograms/l, respectively (p less than 0.05). The sedative effect of clorazepate was less severe in smokers than in non-smokers.
D000284:Administration, Oral; D000328:Adult; D014151:Anti-Anxiety Agents / Q000008:administration & dosage*; D003009:Clorazepate Dipotassium / Q000008:administration & dosage* / Q000378:metabolism; D003975:Diazepam / Q000031:analogs & derivatives*; D006801:Humans; D007700:Kinetics; D008297:Male; D003708:Nordazepam / Q000097:blood / Q000378:metabolism*; D012907:Smoking
D014151:Anti-Anxiety Agents; D003009:Clorazepate Dipotassium; D003708:Nordazepam; D003975:Diazepam