The pharmacokinetics of bisoprolol were investigated following oral administration of 10mg once daily for 7 days in 8 healthy subjects, in 14 patients with different degrees of renal impairment and in 18 patients with liver disease.In healthy subjects peak and trough steady-state concentrations of 52 μg/L and 11 μg/L, respectively, an elimination half-life of 10.0 hours and total body clearance of 14.2 L/h were observed. 5.21 mg/24 hours of unchanged bisoprolol were recovered following urinary excretion during the dosage interval. In 11 patients with renal impairment (mean CLCR=28 ± 5 ml/min/1.72m2) half-life was prolonged to 18.5 hours, and peak and trough concentrations were 74 and 32 μg/L, respectively. Correspondingly, urinary excretion decreased to 3.35 mg/24 hours and total body clearance to 7.8 L/h. In uraemic patients (CLCR<5 ml/min/1.73m2) the total clearance of bisoprolol was 5.0 L/h and the elimination half-life was 24.2 hours. In patients with liver cirrhosis half-life increased to 13.5 hours, steady-state peak and trough concentrations increased to 62 and 22 μg/L, respectively, and total body clearance decreased to 10.8 L/h.The present study indicates that in patients with impairment of kidney or liver function accumulation of bisoprolol above a factor of 2 did not occur. However, in the terminal stages of insufficiency of kidney or liver function bisoprolol dosage should not exceed 10mg.