Tolerance, Safety, and Activity of Rifapentine Alone and in Combination Therapy in AIDS Patients With Mycobacterium Avium Complex Bacteremia.

Inclusion Criteria Patients must have: * Documented positive HIV serology status. * Documented AIDS. * Positive blood culture for MAC from the study-designated microbiology laboratory. NOTE: * Patients with presumed MAC bacteremia, as evidenced by positive blood, bone marrow, or liver biopsy culture analyzed locally, may be enrolled pending confirmation. * Minimum of two MAC-associated symptoms, defined as \>= grade 1 fever; \> grade 1 night sweats, fatigue, diarrhea, abdominal pain, or anorexia; or weight loss \> 5% reported within 4 weeks prior to study entry. * Life expectancy of at least 3 months. Prior Medication: Allowed: MAC prophylaxis with medications other than study drugs (5-day washout period required). Exclusion Criteria Co-existing Condition: Patients with the following symptoms or conditions are excluded: * Pulmonary tuberculosis. * Infections requiring the use of disallowed medications. * Serious diseases that introduce undue risks for adverse reactions to study medication. Concurrent Medication: Excluded: * Terfenadine. * Treatment for pulmonary TB. * Study drugs from an outside source. * Medications with anti-MAC activity (i.e., amikacin, ciprofloxacin, clofazimine, rifampin, and rifabutin). Patients with the following prior conditions are excluded: * History of hypersensitivity to rifabutin, rifampin, clarithromycin, erythromycin, azithromycin, or ethambutol. * Previous episode of uveitis. Prior Medication: Excluded: * Prophylactic treatment for MAC with rifabutin or any of the study medications. * Azithromycin within the 3 weeks prior to randomization. * Any investigational drug during the 4 weeks prior to randomization.