Assessment of a combined preparation of isoniazid, rifampicin and pyrazinamide (Rifater) in the initial phase of chemotherapy in three 6-month regimens for smear-positive pulmonary tuberculosis: a five-year follow-up report.Int J Tuberc Lung Dis 1999; 3(2):126-32IJ
Singapore Tuberculosis Service.
To assess the acceptability, efficacy and relapse rate of a combined formulation of three drugs--isoniazid, rifampicin and pyrazinamide (Rifater)--given in the initial phase of chemotherapy in three 6-month regimens (2SHRZ/4H3R3, 1SHRZ/5H3R3 and 2HRZ/4H3R3) under direct observation for all patients.
A randomised, controlled, unblinded study comparing a group of patients treated with Rifater and another given the three component drugs as separate formulations.
The 310 patients admitted to the study were divided into two groups of 155 patients. The frequency of side effects was similar in both groups. Of 271 patients with drug-sensitive strains who had completed treatment without interruption, sputum cultures converted in all patients. At the end of 5 years, there were 15 relapses: three (2.2%) in the separate drugs group and 12 (9.3%) in the Rifater group. Exclusion of two cases in the Rifater group, one with silicotuberculosis and another with no bacteriological confirmation of diagnosis, gave a relapse rate of 7.9% (P = 0.03 for the comparison of relapse rates in the two groups).
A combined formulation of three drugs given daily in the initial phase of 6-month short-course therapy, followed by intermittent treatment with isoniazid and rifampicin given three times a week under direct observation for all patients, appears to be less effective than treatment with the component drugs given as separate formulations.