Pyrazinamide as a part of combination therapy for BL and LL patients--a preliminary report.

Pyrazinamide in a dose of 1500 mg was given to 63 borderline lepromatous (BL) and lepromatous (LL) leprosy patients on different drug regimens for the initial 2 months of therapy. Fifty-one BL and LL patients were put on the same drug regimens without pyrazinamide. There was a rapid and good clinical improvement in the patients in both of the groups. At the end of 2 years, the patients who received pyrazinamide had a morphological index (MI) of zero as compared to those patients who did not receive pyrazinamide, some of whom still had solidly staining bacilli. One out of 20 (5%) scrotal (smooth muscle) biopsies of the patients who received pyrazinamide had growth in the mouse foot pad as compared to 9 out of 38 (23.7%) smooth muscle biopsies of the patients who did not receive pyrazinamide. At the end of 5 years, the patients who received pyrazinamide had slightly better results compared with the non-pyrazinamide group. Pyrazinamide appears to have some effect against persisters in multibacillary leprosy. A well-controlled, randomized trial with longer duration of pyrazinamide therapy in a larger group of patients needs to be carried out to unequivocally determine the exact role of pyrazinamide in leprosy.