Evaluation of Three Regimens of Chemoprophylaxis for Tuberculosis in Patients co-Infected by HIV and Mycobacterium Tuberculosis

Inclusion Criteria: * HIV infection confirmed by ELISA and Western blot * Age between 18 and 65 years * Life expectancy greater than two years * Reactivity to PPD \> 5 mm Exclusion Criteria: * Presence of active tuberculosis * Background of previous antituberculosis therapy or chemoprophylaxis * Presence of symptoms or signs suggesting pulmonary or extra-pulmonary tuberculosis * History of hypersensitivity to the drugs used in the study (isoniazid, rifampin or pyrazinamide) * Aspartate-aminotransferase and/or alanine-aminotransferase plasma concentrations more than or equal to four times their normal values, total bilirubin more than 2 mg/ml, and/or creatinine more than 2 mg/ml * Pregnancy * Undergoing treatment incompatible with any of the drugs used in the study.