The Effect of Antimicrobial Agents on Bilirubin Binding by Human Erythrocytes

Abstract

Several antimicrobial agents and sodium salicylate were tested for their ability to displace bilirubin from albumin by measuring the increase in bilirubin binding by erythrocytes caused by these drugs in vitro. The ability of the drugs to cause bilirubin displacement seemed to be related to the degree of protein binding of the different drugs, so that substances known to be protein bound to more than 50–60% are potential displacers of bilirubin. Although sulfonamides as a group are thought to be effective displacers of bilirubin, sulfanilamide and sulfadiazine were not found to cause much displacement, probably because of their low protein binding. Most effective displacers were novobiocin, cloxacillin, sulfisoxazole, and salicylate, all known to be almost entirely protein bound. Löwering of the pH level greatly potentiated the displacing effect found.