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. Tanzania/British Medical Research Council Collaborative Investigation.S Afr Med J 1996; 86(8):960-5SA
To evaluate a monthly 'pulse' of rifampicin plus pyrazinamide plus streptomycin in the continuation phase of a short-course antituberculosis regimen.
Randomised controlled trial of two 7-month chemotherapy regimens.
Inpatient chemotherapy and outpatient follow-up in Tanzania.
Smear-positive pulmonary tuberculosis.
All patients received streptomycin plus rifampicin plus isoniazid plus pyrazinamide daily for 6 weeks followed by isoniazid daily for 24 weeks; 50%, at random, received additional doses of rifampicin, pyrazinamide and streptomycin every 4 weeks in the continuation phase. Follow-up continued for 23 months after cessation of chemotherapy.
MAIN OUTCOME MEASURES
Bacteriological failure rate at the end of chemotherapy and relapse rate after stopping.
Of the 266 patients with fully sensitive strains before treatment there was one failure 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% CI 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.
This study was not large enough to demonstrate a significant reduction in the relapse rate from 10% to 5%. If such a reduction were confirmed in a larger study it would represent an important improvement in efficacy. further, in an outpatient setting, the additional monthly doses might improve attendance.