Plasma protein binding of phenytoin and warfarin in patients undergoing renal transplantation.

The plasma protein binding of phenytoin and warfarin was studied in vitro by equilibrium dialysis at 37 degrees C in plasma from patients with chronic renal disease before and after renal transplantation. The plasma protein binding of these two drugs (which is decreased in the uraemic state), increased dramatically during the first 2 to 4 postoperative days and reached values slightly below normal on the 10th to the 15th postoperative day. This increase in binding is suggested to be due to the elimination of inhibiotrs of drug albumin binding, earlier shown to be present in uraemic serum.