Effect of renal impairment on the pharmacokinetics of cibenzoline.

Sixteen subjects completed an open-label study designed to assess the effect of renal impairment on the disposition of cibenzoline. The study included 10 patients with mild or moderate renal impairment creatinine clearance less than 60 ml/min/70 kg) and six healthy subjects in the same age range, each of whom received a single 130 mg oral dose of cibenzoline. The pharmacokinetic parameters observed in the healthy volunteers were similar to those reported previously. Maximum plasma concentration, time of maximum concentration, and apparent volume of distribution after single doses in patients with renal impairment were in the same range as those observed in healthy volunteers. The elimination half-life increased with decreasing renal function from a mean value of approximately 8 hours in healthy volunteers to more than 20 hours in patients with moderate renal impairment. Renal clearance and the fraction of the dose excreted unchanged in the urine decreased with decreasing creatinine clearance. The results of this study suggest that the dosage of cibenzoline should be reduced or the dosage interval increased in patients with reduced renal function to avoid excessive drug accumulation.