Therapeutic effect of fleroxacin against experimental pneumonia in mice.

Fleroxacin is a newly developed quinolone derivative with marked antimicrobial activity. In this study, we have compared the therapeutic effects of fleroxacin with those of ofloxacin, norfloxacin, ciprofloxacin, pipemidic acid and cefaclor against pneumonia in mice caused by Klebsiella pneumoniae. Fleroxacin showed a high therapeutic effect against the experimental pneumonia with an ED50 of 3.4 mg/kg/day, after three times a day oral administration. It was about twice as effective as ofloxacin and ciprofloxacin and more than 15 times more active than norfloxacin. Once or twice a day administration of fleroxacin also showed outstanding therapeutic effects.