The pharmacokinetics of oral nicorandil 20 mg 12 hourly for 9 doses was evaluated in 21 hospitalized patients with angina pectoris due to coronary heart disease and with normal and impaired renal function. Patients were divided into 3 groups based on creatinine clearance (CLCr): GROUP I (n = 6) greater than 80 ml/min, GROUP II (n = 8) 20-80 ml/min, and GROUP III (n = 7) less than 20 ml/min. After the first dose, the total clearance of nicorandil (CL) value did not change with increasing renal failure and so was not dependent on creatine clearance. After the last dose CL was 51 l.h-1 in Group I, 44 l.h-1 in Group II and 56 l.h-1 in Group III, and it was not related to creatinine clearance. The percentage of the dose excreted in the urine was 0.4%. No significant difference was noted in any of the other pharmacokinetic parameters examined in the three groups, not even on comparing values obtained on the first and last days of treatment. The findings suggest that there is no need to change the dose of nicorandil in subjects with different degrees of renal failure.