Split‐drug regimens for the treatment of patients with sputum smear‐positive pulmonary tuberculosis – a unique approach

OBJECTIVE: To evaluate the efficacy of split-drug regimens for treatment of patients with sputum smear-positive pulmonary tuberculosis in south India. DESIGN: Randomized controlled clinical trial where eligible patients were randomly allocated to: (i) 2RE(3)HZ(3)(alt)/4RH(2) (split I): rifampicin plus ethambutol given on one day and isoniazid plus pyrazinamide the next day for first 2 months followed by rifampicin plus isoniazid twice weekly for 4 months, or (ii) 3RE(3)HZ(3)(alt)/3RH(2) (split II): similar to regimen 1, except duration was 3 months in each phase, or (iii) 2REHZ(3)/4RH(2) (control): rifampicin, isoniazid, ethambutol and pyrazinamide, given thrice weekly for 2 months followed by isoniazid and rifampicin twice weekly for 4 months. All patients were followed up clinically and bacteriologically every month up to 2 years and every 6 months for up to 5 years. RESULTS: A favourable response (cultures negative for Mycobacterium tuberculosis during the last 2 months of treatment) was observed in 91% of 407 patients in split I, 94% of 415 in split II and 89% of 418 in the control regimen. Ninety-one per cent of 370 patients in split I, 93% of 389 in split II and 90% of 370 in control regimens had quiescent disease at the end of 60 months. Gastrointestinal symptoms were more frequent under the control regimen (P = 0.01). CONCLUSION: Split-drug regimens were as effective as the control regimen in terms of favourable response at the end of treatment and quiescent disease at 5 years, and caused fewer gastrointestinal side-effects.