Disposition of oxazepam in relation to age, sex, and cigarette smoking.
The kinetics of single 30-mg oral doses of oxazepam were determined in 22 male and nine female volunteers aged 20-86 years. Oxazepam plasma concentrations were measured in multiple plasma samples drawn during 36 h after each dose. Mean kinetic variables in males and females, respectively, were: elimination half-life, 7.5 and 8.5 h; volume of distribution, 0.96 and 1.17 l/kg; clearance, 1.48 and 1.70 ml/min/kg. Sex differences were not significant, nor were any of the kinetic variables significantly related to age. However, oxazepam clearance increased significantly with heavier cigarette smoking (r = 0.48, p less than 0.01). Mean clearance in smokers (1.98 ml/min/kg) was significantly higher than in nonsmokers (1.23 ml/min/kg, p less than 0.01). Thus, smoking is a more important determinant of oxazepam clearance than age or sex.
D000328:Adult; D000368:Aged; D000375:Aging; D005260:Female; D006801:Humans; D007408:Intestinal Absorption; D007700:Kinetics; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D010076:Oxazepam / Q000097:blood*; D012737:Sex Factors; D012907:Smoking
D010076:Oxazepam