A controlled trial to compare the therapeutic effects of dapsone in combination with daily or once-monthly rifampin in patients with lepromatous leprosy.

In this controlled trial in 35 patients with lepromatous leprosy the therapeutic effects of adding rifampin 450 mg daily (Regimen A) or 1200 mg once a month (Regimen B) to a standard dapsone regimen of 50 mg daily were practically identical. Moderate to marked clinical improvement was observed in 88% and 83% of the patients treated with Regimens A and B respectively. The average rates of decrease in the MI of the skin smears and nose-blow smears were similar. The average decreases in the BI of the skin smears were 0.7 and 0.6 in patients on the Regimen A and B respectively. Following 6 months' treatment with Regimens A and B the average decreases in the Logarithmic Bacterial Indexes of Biopsies were 4.7% and 7% respectively. The once-monthly rifampin schedule was well tolerated and did not lead to "flu" syndrome, anuria, oliguria, hemolytic anemia, thrombocytopenia, or anaphylactic shock. This trial revealed the satisfactory efficacy, good tolerability, and practicability of a supervised once-monthly 1200 mg single oral dose rifampin schedule as a component of combination regimes for the initial treatment of patients with lepromatous (LLs and LLp) leprosy.