Controlled clinical trial of four short-course regimens of chemotherapy for two durations in the treatment of pulmonary tuberculosis: first report: Third East African/British Medical Research Councils study.

A comparison was made between 4 regimens of chemotherapy given for 6 or 8 months, with a 6-month period of follow-up thus far. One regimen, which had a 2-month initial intensive phase of streptomycin, isoniazid, rifampin, and pyrazinamide followed by daily administration of thiacetazone and isoniazid, was very effective. Shortening the initial intensive 4-drug phase to 1 month produced a less successful regimen unless the continuation phase was twice-weekly administration of streptomycin, isoniazid, and pyrazinamide. A regimen in which pyrazinamide was omitted from the initial intensive 2-month phase was also less effective. All patients were inpatients for 6 months to ensure that every dose of drug was fully supervised during this period. Increasing the total duration of chemotherapy from 6 months to 8 months was associated with a significant decrease in the early relapse rate in all 4 regimens, although the above differences between the regimen remained. The applicability of the findings is discussed.