Further study of the effectiveness of single doses of clarithromycin and minocycline against Mycobacterium leprae in mice.

The anti-Mycobacterium leprae activities of single doses of rifampin (RMP), clarithromycin (CLARI), or minocycline (MINO) alone, and various combinations of CLARI + MINO were determined in immunocompetent mice by the kinetic method. A single dose of RMP 10 mg/kg, CLARI 100 mg/kg or 200 mg/kg, MINO 25 mg/kg or 50 mg/kg alone, or various combinations of CLARI & MINO were active. RMP was more active than the other treatments; the activity of CLARI 100 mg/kg was greater than that of 50 mg/kg, but did not differ significantly from that of 200 mg/kg; MINO 50 mg/kg was more active than 25 mg/kg; and none of the combinations of CLARI + MINO was more active than any of the stronger components administered alone. Therefore, both CLARI and MINO may be applied, either alone or in combination, as components of monthly administered, fully supervised, multidrug regimens for the treatment of multibacillary leprosy. Taking into account the effectiveness of the drugs and the comparative pharmacokinetic data, we propose that the optimal dosage in human trials is CLARI 1000 mg per month or MINO 200 mg per month.