Plasma protein binding and distribution characteristics of drugs as indices of their hemodialyzability.

The dialysis clearance, plasma protein binding, and distribution (expressed as volume of distribution) characteristics of a drug were evaluated as predictive indices of the efficiency of hemodialysis in removing drug from the body. Dialysis clearance correlated poorly with the fraction of drug in the body removed by hemodialysis. The best predictive measure of hemodialysis efficiency was obtained by a nonlinear model relating the ratio of the percent of free drug in the plasma and the volume of distribution of the drug to the fraction removed. Knowledge of the binding and distribution characteristics of a drug provides insight into the dialyzability of a drug which in turn may assist in coming to decisions on the necessity of dose adjustments for patients on chronic hemodialysis and the rational use of hemodialysis in the treatment of drug intoxication.