Removal of cimetidine by peritoneal dialysis, hemodialysis, and charcoal hemoperfusion

Dialysis clearance of cimetidine in patients receiving peritoneal dialysis, hemodialysis, and hemoperfusion was compared in stable and seriously ill patients. Two methods of determining dialysis clearance were employed, one of which was the method employed for cimetidine previously in the literature. Cimetidine clearance was lowest for peritoneal dialysis (5 ml/min), intermediate for hemodialysis (28 ml/min), and greatest for hemoperfusion (85 ml/min). Using both methods to calculate dialysis clearance, we found that cimetidine clearance during dialysis has been overestimated. In addition, pharmacokinetic analysis revealed that peritoneal and hemodialysis apparently removed cimetidine from the central compartment only, whereas hemoperfusion apparently removed drug from the peripheral compartment as well. A possible mechanism to explain this difference is based on the observation that hemodynamic changes occur during hemodialysis that may not be seen during hemoperfusion. No dosage adjustment need be made when patients receiving cimetidine undergo any form of dialysis; hemoperfusion may be of some benefit in removing drug from the central as well as tissue compartments in an acute overdose situation.