Pharmacokinetics of cimetidine in patients undergoing hemodialysis

In order to establish improved guidelines for dosage adjustments of cimetidine before and during hemodialysis, the kinetics of this drug was investigated in 7 uremic patients undergoing regular hemodialysis. The absorption fraction was found to be 0.75 (range 0.61-0.86), the terminal half-life in plasma between 138 and 238 min, the total body clearance (Cltotal) between 178 and 337 ml/min, and the apparent volume of distribution about 1 l/kg. During hemodialysis no excess amounts of cimetidine were removed from serum. In 3 patients a weak rebound phenomenon was seen after hemodialysis. Based on the Cltotal obtained in this study, dosage schemes producing a 24-hours mean steady state concentration from 0.60 (2.38) to 1.20 (4.76) mg/l (mumol/l) are suggested.