A Study of Rifabutin, Used Alone or With Ethambutol in the Prevention of Mycobacterium Avium Complex (MAC) Bacteremia in Patients With AIDS

Inclusion Criteria Concurrent Medication: Required: AZT, d4T, ddI, or ddC. Antipneumocystis prophylaxis. Allowed: Short course (< 14 days) of ciprofloxacin for acute infections. Patients must have: AIDS. CD4 count <= 100 cells/mm3. NO prior or current MAC infection. Prior Medication: Required: Antipneumocystis prophylaxis for at least 4 weeks prior to study entry. Allowed: Prior rifabutin. Prior ethambutol. Prior clarithromycin. Exclusion Criteria Co-existing Condition: Patients with the following symptoms or conditions are excluded: Positive tuberculin skin test (PPD > 5 mm). Active M. tuberculosis. Perceived as unreliable or unavailable for frequent monitoring. Concurrent Medication: Excluded: Other antiretrovirals not specifically allowed. All investigational drugs. Other antimycobacterial therapy, such as clarithromycin, azithromycin, rifampin, clofazimine, amikacin, streptomycin, isoniazid, cycloserine, ethionamide, and ciprofloxacin (>= 14 days). Patients with the following prior conditions are excluded: Known hypersensitivity to rifabutin, rifampin, or other rifamycins and/or ethambutol. Prior Medication: Excluded within 4 weeks prior to study entry: Rifampin. Isoniazid. Clofazimine. Cycloserine. Ethionamide. Amikacin. Ciprofloxacin.