Short-course chemotherapy in pulmonary tuberculosis. A controlled trial by the British Thoracic and Tuberculosis Association.

The results of short courses of chemotherapy using rifampicin plus isoniazid, supplemented for the first two months by streptomycin or ethambutol, in patients with newly diagnosed pulmonary tuberculosis, have been studied. 174 patients with little or no cavitation received six months chemotherapy. 1 (0.6%) failed to convert to culture negative during treatment and 5 (3%) relapsed in the twelve months after the end of treatment. In 177 patients with similar disease, twelve months chemotherapy was 100% effective in rendering the sputum culture negative and in preventing relapse in the six months after the end of treatment. 151 patients with more extensive cavitation received chemotherapy for nine months; this was 100% effective in sputum conversion and in preventing relapse in the nine months after the end of treatment. In 155 patients with similar disease, the eighteen-month regimen was uniformly successful in sputum conversion. The rifampicin plus isoniazed regimen was well tolerated, producing adverse effects which warranted withdrawal from the study in only 3.6% of patients. Comparison of ethambutol with streptomycin as a third drug given for the first eight weeks showed no significant difference in the rate of sputum conbersion nor in the incidence of relapse. Streptomycin produced significant adverse effects in 8% of patients whilst ethambutol caused none. Chemotherapy with rifampicin plus isoniazed for nine months, supplemented initially by ethambutol, is more acceptable than standard chemotherapy for eighteen months, is highly effective in sputum conversion, and has resulted in no relapses over a nine-month follow-up period. Further follow-up is being continued to confirm that relapse does not occur.