[The importance of the albumin bilirubin binding in drug therapy in the newborn].

Bilirubin encephalopathy in the newborn is caused not so much by the level of total serum bilirubin but rather by the level of free bilirubin not bound to albumin. Compared to adults prematures and newborns show a higher tendency towards separation of bilirubin from the albumin bond which is statistically significant as could be demonstrated by measurements in serum and plasma. This might be due to a lower bilirubin binding capacity of the neonatal albumin or a competitive displacement of the bilirubin from the albumin bonds by unknown endogenous substances. The influence of several drugs, of blood exchange transfusion and of light in phototherapy on the cleavage of bilirubin from its albumin bond was examined. Some drugs, but not the phototherapylight, enhanced displacement.