Cimetidine kinetics in renal transplant recipients.

Single dose kinetics of cimetidine (Ci) were investigated in 10 patients with renal impairment of varying degrees after renal transplantation. Thirteen healthy subjects and 7 patients with stable renal insufficiency served for control. The studied groups showed no difference in the non-renal Ci-clearance (Clnr) and the volume of distribution at steady state (Vdss). The renal Ci-clearance (Clr) declined parallel to renal function, whereas the estimation of renal tubular transport capacity (Clr/endogenous creatinine-clearance) was independent of renal function in either group studied. The healthy subjects and the control-patients showed a significant correlation between the reduction of the total Ci-clearance (ClB) and the endogenous creatinine-clearance (Clcrea) (ClB = 192 +/- 3.8 Clcrea, p less than 0.001). The individual ClB-values of the patients after kidney transplantation were found within the 90% confidence intervals of this regression line. According to these findings, dosage adjustments of Ci on the basis of Clcrea measurements appear to be valid for renal transplant recipients.