A study of two twice-weekly and a once-weekly continuation regimen of tuberculosis chemotherapy, including a comparison of two durations of treatment. 2. Second report: the results at 36 months.

The final results of a controlled clinical trial of 3 chemotherapeutic regimens in pulmonary tuberculosis in Czechoslovakia are presented. Two of the regimens were based on a twice-weekly continuation regimen of streptomycin plus isoniazid, preceded by 6 weeks or 13 weeks of initial daily triple chemotherapy with streptomycin, PAS and isoniazid; the third regimen was once-weekly streptomycin plus isoniazid preceded by 13 weeks of the daily triple combination. Patients in each regimen were allocated to a total duration of treatment of 12 months or 18 months. At 3 years, the twice-weekly continuation regimen was highly satisfactory, 97% of 93 patients receiving 13 weeks of initial daily triple chemotherapy and 98% of 82 receiving 6 weeks having a favourable response. The once-weekly regimen was less satisfactory and this was largely due to the rapid acetylators of isoniazid of whom 78% of 37 had a favourable response compared with 97% of 60 slow acetylators. There was no advantage in the longer course of chemotherapy, for 95% of 129 patients receiving chemotherapy for 12 months had a favourable response compared with 95% of 143 patients receiving it for 18 months.