Cytochrome contraceptive agents

Rifampicin is a potent inducer of cytochrome P450 enzymes and thus can diminish the activity of a multitude of other agents such as warfarin, gluco-corticosteroids, cyclosporin, oral contraceptives and sulphonylurea-type oral antidiabetic agents. 

With the introduction of RiF in 1967, the duration of combination therapy for the treatment of TB was significantiy reduced (from 18 to 9 months). Rifampin is nearly always used in combination with one or more other antitubercuiin agents. The drug is potentially hepatotoxic and may produce Gl disturbances, rash, and thrombocytopenic purpura. Rifampin is known to induce hepatic microsomai enzymes (cytochrome P450) and may decrease the effectiveness of oral contraceptives, corticosteroids, warfarin, quinidine, methadone, zidovudine, clarithromycin, and the azoie antifungai agents (see Chapter 10) (33). 

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