Comparison of daily and twice-weekly regimens to treat pulmonary tuberculosis.

A randomised controlled trial compared the effectiveness and toxicity in pulmonary tuberculosis of two drug regimens containing rifampicin and isoniazid given daily or twice-weekly for 4 months after a 2-month period of intensive treatment with daily isoniazid, rifampicin, and pyrazinamide. 667 patients with newly diagnosed pulmonary tuberculosis were randomly allocated to continue daily treatment with isoniazid (400 mg) and rifampicin (600 mg) or to twice-weekly treatment with isoniazid (900 mg) and rifampicin (600 mg). 544 of the 667 patients (81%) completed the 6-month course (287 of 337 [85%] treated daily and 257 of 330 [79%] treated twice-weekly). Drug toxicity was not a great problem; the treatment was permanently discontinued in only 2% of patients. There was no significant difference at the end of months 5 and/or 6 of chemotherapy between the groups treated daily and twice-weekly in the proportions with bacteriological failure (at least one positive sputum culture with more than 20 colonies) or who had died from tuberculosis (17 [6%] vs 10 [3%]). Nor was there a significant difference in the relapse rate (17 [7%] treated daily vs 10 [4%] treated twice-weekly) during follow-up of 12 months. Thus, the twice-weekly regimen was at least as effective as the daily regimen for treatment of pulmonary tuberculosis.