Pharmacokinetic study of lafutidine in patients under hemodialysis

H2-receptor antagonist is an effective drug for peptic ulcers in hemodialysis patients. It was reported that the urinary excretion rate of lafutidine, a new H2-receptor antagonist was lower than those of other H2-receptor antagonists, and the plasma concentration profiles of lafutidine in elderly subjects with renal dysfunction [Ccr: 20-60 (average: 45.2) mL/min] were similar to those in elderly subjects with normal renal function (Ccr: ≥61mL/min) and healthy subjects. In the present study, we evaluated pharmacokinetics of lafutidine in hemodialysis patients. A lafutidine tablet (10mg) was given to 6 patients during the inter- and intra-dialysis period. The age of these patients was between 49 and 72 years, and the duration of dialysis was between 11 months and 14 years. Plasma concentration of lafutidine were determined to obtain pharmacokinetic parameters. In addition, the extraction rate of lafutidine by hemodialysis was measured. When lafutidine was orally administered without hemodialysis, Tmax of 0.8±0.1hr, Cmax of 336±40ng/mL, t1/2 of 6.71±0.30hr, and AUC(0-24hr) of 2278±306ng·hr/mL were obtained. After hemodialysis, Tmax of 2.6±0.5hr, Cmax of 226±36ng/mL, t1/2 was 4.57±0.24hr, and AUC(0-6hr) of 853±128ng·hr/mL were obtained. In addition, lafutidine was extracted by all hemodialysis membranes used in this study with a 7 to 18% extraction rate. t1/2 of lafutidine was not prolonged even in patients with loss of renal function. Prolonged t1/2 (6.7hr) was less than the administration period (every 12hr) indicating that the administration pattern of lafutidine need not change for hemodialysis patients. However, Cmax was approximately doubled in hemodialysis patients administered oral lafutidine compared to that in healthy subjects. Therefore, it might be preferable to initiate administration of lafutidine at a lower dose.