Ofloxacin for the treatment of leprosy.

Among the major commercially available fluoroquinolones, ciprofloxacin was inactive against M. leprae in mice; pefloxacin was active, 50 mg/kg daily showed bacteriostatic activity but 150 mg/kg daily displayed bactericidal activity; ofloxacin was more active than pefloxacin, 50 mg/kg daily exerted the same level of bactericidal effect as pefloxacin 150 mg/kg daily, and ofloxacin 150 mg/kg displayed profound killing activity. Two clinical trials with 6 months of pefloxacin and/or ofloxacin in 31 previously untreated lepromatous patients have been completed. Pefloxacin 400 mg twice daily or 800 mg once daily or ofloxacin 400 mg once daily were equally effective; definite clinical improvement with drastically decrease of morphological index to the baseline were observed in all patients at 2 months after beginning of treatment; about 99.99%, or 4 "logs", of organisms viable on Day 0 were killed by 22 doses of either pefloxacin or ofloxacin. The side effects from the two trials were rare and mild, and the patients tolerated extremely well the combinations of pefloxacin/ofloxacin plus multidrug therapy (MDT) regimen for multibacillary leprosy recommended by WHO. The amount of rifampicin-resistant mutants in lepromatous patients before treatment are no more than 4 "logs", thus, all rifampicin-resistant mutants may be eliminated by 22 doses of either pefloxacin or ofloxacin. It is, therefore, possible that the combination of ofloxacin and rifampicin may considerably shorten the required duration of MDT.