Rifabutin, a rifamycin derivative like rifampicin, has been registered for the treatment of pulmonary tuberculosis and for the prophylaxis and treatment of MAC in patients with AIDS. Rifabutin induces cytochrome P-450 3A4. The effect of rifabutin on the pharmacokinetics and metabolism of drugs administered concomitantly to humans (isoniazid, ethambutol, zidovudine, didanosine, delavirdine, fluconazole, itraconazole, methadone, clarithromycin, theophylline and cyclosporin) has been reviewed.