Objective: To determine the principal adverse effects of the tuberculosis treatment regimen recommended by the Brazilian Ministry of Health. Methods: A prospective descriptive study involving 79 tuberculosis patients treated at the Clinical Research Center of the Cassiano Antonio Moraes University Hospital, in the city of Vitória, Brazil, between 2003 and 2006. The treatment regimen consisted of isoniazid, rifampicin, pyrazinamide and ethambutol for four months, followed by rifampicin and isoniazid for two months. During the treatment period, the patients were clinically evaluated every week and had a monthly medical visit. Results: The overall incidence of adverse effects was 83.54%. Articular/bone/muscle involvement was the most common, followed by skin involvement (24.94% and 22.09%, respectively). Adverse effects were more common in the second month of treatment (41.59%). Modification of the treatment regimen was unnecessary. One patient required concomitant medication to counter the adverse effects. The cure rate was 100%. Conclusions: The overall incidence of adverse effects related to the new treatment regimen recommended by the Brazilian Ministry of Health was high. However, none of those effects demanded a change in the regimen, which was effective in the patients evaluated.

Keywords: Treatment outcome;Tuberculosis; Antitubercular agents; Adverse drug reaction reporting systems.