Chemotherapeutic efficacy of ofloxacin against experimental pneumonia with Pseudomonas aeruginosa in guinea pigs.

The chemotherapeutic efficacy of ofloxacin against experimental pneumonia was investigated with special reference to its treatment regimen. A pneumonia model was successfully produced by inhalation of a virulent strain of Pseudomonas aeruginosa in guinea pigs immunosuppressed with cortisone acetate. One or 4 days after infection, the animals were treated orally with the fixed daily doses of ofloxacin either once a day or thrice a day for 3 consecutive days. Ofloxacin given thrice a day eliminated the organisms from the lung more efficiently than the equivalent total doses injected once a day in both series of treatment, starting 1 or 4 days after infection. The superiority of the triple dosing in chemotherapeutic efficacy of ofloxacin was found to be attributable at least to the longer retention of its pulmonary levels exceeding the antibiotic concentrations.