Interaction of Ketoconazole with Rifampin and Isoniazid

Abstract

RIFAMPIN stimulates proliferation of the smooth endoplasmic reticulum of hepatocytes and induces microsomal enzymes involved in drug metabolism.1 It was recently reported that concurrent administration of rifampin and ketoconazole resulted in decreases in the expected serum concentrations of ketoconazole.2 , 2a We report here on a patient in whom both antifungal and antituberculous therapy failed to exert their expected effects when the drugs were administered concurrently. Pharmacokinetic studies demonstrated that this therapeutic failure was related to drug interactions resulting in markedly diminished serum concentrations of rifampin and ketoconazole.MethodsOur patient was first evaluated at Oklahoma Children's Memorial Hospital at 17 . . .