Repeated diazepam dosing in cirrhotic patients: cumulation and sedation

Five medically stable male patients with cirrhosis and four healthy age- and sex-matched controls received single 5-mg oral doses of diazepam (DZ) daily for 22 consecutive days. Plasma concentrations of DZ and its major metabolite desmethyldiazepam (DMDZ) were measured daily during the period of dosing and in the 7-day washout period that followed. Clinical self-ratings of sedation, fatigue, mood state, and sleep patterns were obtained daily during the period of dosage with the use of visual analogue scales. Steady-state plasma DZ concentrations were higher (165 and 98 ng/ml), and DMDZ concentrations tended to be higher (399 and 206 ng/ml), in cirrhotics than in controls. Increases in self-rated daytime sedation also were greater in cirrhotics than in controls and correlated strongly with total DZ and DMDZ plasma concentration during the first 2 wk of diazepam dosing. Thus, reduced clearance of DZ in cirrhotics leads to increased cumulation during long-term dosing. This in turn is associated with increased clinical sedation. Sedative effects are partly offset as treatment proceeds because of adaptation or tolerance. Based on kinetic findings, diazepam can be given safely to cirrhotic patients provided daily dosage is reduced by approximately 50%.