COMPARISON BETWEEN SM DAILY AND TWICE WEEKLY TREATMENT IN THE REGIMEN OF SM, INH AND PAS

Particularly Considering the Degree of Drug Resistance (Report 2)

Abstract

Following the previous report, we studied the possible difference in the conversion rate and the speed of conversion between SM daily (A) and twice weekly (B) groups treated with the combined regimen of SM 1.0 g, INH 0.6 g and PAS 10.0 g. The difference from the previous study was the dose of INH (0.6 instead of 0.3 g in the previous study) and the SM sulfate instead of DHSM.
The patients were chosen from those admitted to the National Nakano Chest Hospital during the period from November 1971 to April 1974. All of them had cavity and were smear positive for tubercle bacilli in their sputum. They had not been treated or else treated previously only for less than 15 days.
These patients were allocated at random to these two groups. Drug sensitivity tests were done by Canetti's proportion method. A strain was defined as sensitive if a growth on media containing either of SM 4μg/ml, INH 0.1μg/ml and PAS 0.5μg/ml was less than 1% of the growth on the control.
Exclusion and dropout cases were more in number compared with the previous study, and this was due to the increase in the number of resistant cases to SM (especially to 4 μg/ml) and cases showing side-effects to SM (Table 2 and 11).
Background factors were almost the same between the two groups (Fig.1).
Among cases treated throughout one year (Fig.2), there was no significant difference in the conversion rate and the speed of conversion between groups A and B; that is, 56 cases converted to negative among 57 cases of group A and all cases converted among 61 cases of group B. Only one exceptional case of group A was a peculiar one who was sensitive at the start of chemotherapy but during the course of treatment with SM, INH and PAS, it suddenly became resistant to all drugs, not only to SM, INH and PAS but also to RFP, EB, TH, CS, etc. (Table5). This strain was niacin positive and could not grow on PNB culture media which means that the bacilli were human type.
In other words, there were no significant difference in the conversion rate and the speed of conversion by the interval of SM administration (daily or twice weekly) and between the dose of IINTH (0.6g or 0.3g).
Most of the cases converted to negative within 6 months from the beginning of the tripple regimen. Cases converted after six months were illustrated in Table 7.
It is worth while to mention that there was no bacillary relapse during the course of treatment at least for one year.
The incidence of hearing impairment was less in this study treated by SM sulfate than the previous one treated with DHSM; that is, 3.7% in group A and 0.7% in group B. Its grade was slight and no one had a trouble in daily conversation. However, there were quite a number of patients who lost the feeling of equillibrium and had allergic reactions (Table 11).