To evaluate and compare the safety and effectiveness of a one-year course of isoniazid (INH) versus a two-month course of rifampin plus pyrazinamide for the prevention of reactivation tuberculosis in individuals infected with both HIV and latent (inactive) Mycobacterium tuberculosis.

Current guidelines from the American Thoracic Society and the Centers for Disease Control recommend 6 to 12 months of INH for PPD (purified protein derivative)-positive individuals. Although the effectiveness of this treatment is not known for HIV-infected individuals, several studies using INH to prevent tuberculosis in presumably normal hosts have shown 60 to 80 percent effectiveness. Problems with this treatment include compliance, adverse reaction, and the possibility of not preventing disease due to tuberculosis organisms being resistant to INH. A two-month preventive treatment plan should help in increasing compliance. In addition, the use of two drugs (rifampin / pyrazinamide) may help overcome problems with drug resistance. If this study shows equal or greater effectiveness of the two-month rifampin / pyrazinamide treatment, it could alter the approach to tuberculosis prevention for both HIV-positive and HIV-negative individuals.

Current guidelines from the American Thoracic Society and the Centers for Disease Control recommend 6 to 12 months of INH for PPD (purified protein derivative)-positive individuals. Although the effectiveness of this treatment is not known for HIV-infected individuals, several studies using INH to prevent tuberculosis in presumably normal hosts have shown 60 to 80 percent effectiveness. Problems with this treatment include compliance, adverse reaction, and the possibility of not preventing disease due to tuberculosis organisms being resistant to INH. A two-month preventive treatment plan should help in increasing compliance. In addition, the use of two drugs (rifampin / pyrazinamide) may help overcome problems with drug resistance. If this study shows equal or greater effectiveness of the two-month rifampin / pyrazinamide treatment, it could alter the approach to tuberculosis prevention for both HIV-positive and HIV-negative individuals.

Patients are chosen by a random selection process to either the INH or the rifampin / pyrazinamide arm of the dose. Patients on the INH arm receive INH plus vitamin B6 (pyridoxine hydrochloride ) daily for 12 months. Patients on the other arm receive rifampin plus pyrazinamide for 60 days. Dosage of rifampin and pyrazinamide depends on weight of patient.

Inclusion Criteria

Concurrent Medication:

Allowed:

• Antiretroviral treatment.
• Pneumocystis carinii pneumonia prophylaxis.
• Treatment for acute opportunistic infection.

Patients must have:

• HIV infection.
• Current or documented history of positive PPD skin test.
• Life expectancy of at least 6 months or, in the physician's opinion, patient has a reasonable chance of survival to end of study.

Allowed:

• Participation in other clinical trials as long as there is no potential activity of other study drugs against Mycobacterium tuberculosis (MTb), additive toxicities between study agents, or known possible drug interactions between study drugs.

Exclusion Criteria

Co-existing Condition:

Patients with the following conditions or symptoms are excluded:

• Current active clinical tuberculosis, confirmed or suspected.
• History of sensitivity / intolerance to any study medication.
• Evidence of peripheral neuropathy, i.e., signs or symptoms of paresis, paresthesias, neuromotor abnormalities, or neurosensory deficits of grade 3 or worse.
• Unwilling or unable to have current therapy and/or concomitant medication changed to avoid serious interaction with study medication.
• Acute hepatitis.
• Unable to comply with the follow-up requirements of the protocol.

Concurrent Medication:

Excluded:

• Treatment with quinolones, fluoroquinolones, aminoglycosides, or other agents that have activity against Mycobacterium tuberculosis.
• Excluded as ongoing (i.e., continuous, chronic and/or recurring) treatment:
• Aminoglycosides such as amikacin, aminosalicylic acid salts (PAS), capreomycin, clofazimine, cycloserine, ethambutol, ethionamide, isoniazid (INH) if randomized to rifampin/pyrazinamide arm of study, kanamycin, pyrazinamide if randomized to INH arm of study, and quinolones and fluoroquinolones, i.e., rifabutin, rifampin (if randomized to INH arm of study), ciprofloxacin, levofloxacin, ofloxacin, streptomycin, and thiacetazone.

Prior Medication:

Excluded:

• More than 2 months of continuous treatment, after documentation of a positive PPD skin test, with agents that have known or potential antituberculous activity or any antimycobacterial medication for > 1 month.

Patients may not have the following prior conditions:

• History of sensitivity / intolerance to any study medication.
• Unwilling or unable to comply with the follow-up requirements of the protocol.