A CONTROLLED TRIAL OF A 4-WEEKLY SUPPLEMENT OF RIFAMPICIN, PYRAZINAMIDE AND STREPTOMYCIN IN THE CONTINUATION PHASE OF A 7-MONTH DAILY CHEMOTHERAPY REGIMEN FOR PULMONARY TUBERCULOSIS

Objective. To evaluate a monthly 'pulse' of rifampicin plus pyrazinami de plus streptomycin in the continuation phase of a short-course antit uberculosis regimen. Design. Randomised controlled trial of two 7-mont h chemotherapy regimens. Setting. Inpatient chemotherapy and outpatien t followup in Tanzania. Patients. Smear-positive pulmonary tuberculosi s. Intervention. All patients received streptomycin plus rifampicin pl us isoniazid plus pyrazinamide daily for 6 weeks followed by isoniazid daily for 24 weeks; 50%, at random, received additional doses of rifa mpicin, pyrazinamide and streptomycin every 4 weeks in the continuatio n phase, Follow-up continued for 23 months after cessation of chemothe rapy. Main outcome measures. Bacteriological failure rate at the end o f chemotherapy and relapse rate after stopping. Results. Of the 266 pa tients with fully sensitive strains before treatment there was one fai lure in each series during chemotherapy; after stopping, 5% of the 114 who received the supplement relapsed bacteriologically compared with 10% of the 113 who did not (95% Cl for the difference -0.02% to +11.3% ), The results in the 37 patients with strains resistant to isoniazid pretreatment were not as good, but similar for the two regimens. Concl usion. This study was not large enough to demonstrate a significant re duction in the relapse rate from 10% to 5%, If such a reduction were c onfirmed in a larger study it would represent an important improvement in efficacy. Further, in an outpatient setting, the additional monthl y doses might improve attendance.