Rate of relapse in multibacillary patients after cessation of long-course dapsone monotherapy supplemented by a final supervised single dose of 1500 mg of rifampin.

When multidrug therapy was implemented in Senegal, 406 multibacillary (MB) patients who had been treated for more than 10 years by dapsone alone, and who had become clinically inactive and skin-smear negative, were released from treatment. Of these 406 patients, 298 were given a supervised single dose of 1500 mg of rifampin. Subsequently, 302 of them (229 who had been given rifampin and 73 who had not) were followed up by means of annual clinical and bacteriological examinations. Of the former 229 followed up for a mean period of 4.9 years, 34 patients relapsed (22 males and 12 females), giving a crude relapse rate of 15% and an overall risk of relapse of 3.1 per 100 patient-years. Of the latter 73 followed up for a mean period of 2.4 years, 5 relapsed (4 males and 1 female), giving a crude relapse rate of 6.8% and an overall risk of relapse of 2.9 per 100 patient-years. Such results, which are in agreement with those of a similar study conducted recently in Mali, indicate that the intake of a single dose of 1500 mg of rifampin by MB patients when they are released from long-course dapsone monotherapy does not result in a decrease of the relapse rate. Therefore, MB patients who have been treated with dapsone alone, even for long periods, should be put under multidrug therapy prior to their release from control.