The pharmacokinetics of a single 30-mg oral dose of oxazepam was evaluated in seven patients with chronic renal failure on maintenance hemodialysis and in seven healthy controls matched for age and sex. Based on total (free plus bound) serum oxazepam concentrations, elimination half-life was prolonged in renal patients compared to controls (22 vs 8 h,p<0.001) and="" volume="" of="" distribution="" increased="" (3.0="" vs="" 1.4="">p<0.02). however,="" total="" clearance="" was="" similar="" between="" groups="" (1.8="" vs="" 1.9="" ml/min="" per="" kilogram).="" these="" findings="" were="" confounded="" by="" the="" increased="" oxazepam="" free="" fraction="" in="" serum="" of="" renal="" failure="" patients="" (10.3%)="" as="" compared="" to="" healthy="" controls="" (4.3%).="" correction="" for="" differences="" in="" binding="" indicates="" similar="" distribution="" of="" unbound="" oxazepam="" between="" groups,="" but="" reduced="" clearance="" of="" pharmacologically="" active="" unbound="" oxazepam="" in="" renal="" patients="" (18="" vs="" 45="" ml/min="" per="" kilogram).="" oxazepam="" dosage,="" therefore,="" may="" require="" downward="" adjustment="" for="" renal="" failure="" patients="" on="">