Drug therapy in patients undergoing haemodialysis. Clinical pharmacokinetic considerations.

Haemodialysis is utilised therapeutically as supportive treatment for end-stage renal disease (ESRD). In conjunction with haemodialysis therapy, ESRD patients frequently receive a large number of drugs to treat a multitude of intercurrent conditions. Because of the impaired renal function in ESRD patients, dosage reduction is often recommended to avoid adverse drug reactions, particularly for drugs and active metabolites with extensive renal excretion. On the other hand, if the removal of a drug by haemodialysis during concomitant drug therapy is significant, a dosage supplement would be required to ensure adequate therapeutic efficacy. Knowledge of the impact of haemodialysis on the elimination of specific drugs is therefore essential to the rational design of the dosage regimen in patients undergoing haemodialysis. This review addresses the clinical pharmacokinetic aspects of drug therapy in haemodialysis patients and considers: (a) the effects of ESRD on the general pharmacokinetics of drugs; (b) dialysis clearance and its impact on drug and metabolite elimination; (c) the definition of dialysability and the criteria for evaluation of drug dialysability; (d) pharmacokinetic parameters which are useful in the prediction of drug dialysability; and (e) the application of pharmacokinetic principles to the adjustment of dosage regimens in haemodialysis patients. Finally, drugs commonly associated with haemodialysis therapy are tabulated with updated pharmacokinetics and dialysability information.