During the treatment with rifampicin some patients will have mild elevation in the bilirubin with normal transaminases.This is due to:
One form of hepatic adaptation includes drug induced hyperbilirubinemia , it is seen with rifampicin,flavaspidic acid,cyclosporine. Ref : Schiff's diseases of liver , Edition -11 , Page - 715.
Hemolysis
Transient cholestasis with bile duct injury
Microsomal enzyme induction
Hepatic adaptation