To evaluate the efficacy, safety and usefulness of lomefloxacin (NY-198), a new synthetic quinolone antimicrobial agent, in respiratory tract infections (bacterial pneumonia and chronic respiratory infections), we carried out a double-blind comparative study with cefaclor (CCL) as a reference drug. NY-198 at daily doses of 600 mg (3 divided doses) and 1, 500 mg of CCL (3 divided doses) were orally administered for 14 days, and the following results were obtained: 1) Of a total of 358 patients (180 in the NY-198 group and 178 in the CCL group), 290 (146 in the NY-198 group and 144 in the CCL group) were assigned by the committee for the evaluation of efficacy, 333 (167 and 166, respectively) for evaluation of side effects, 305 (156 and 149, respectively) for evaluation of abnormal changes in laboratory findings and 298 (152 and 146, respectively) for evaluation of usefulness. There were no significant differences between the two groups with respect to the rate of exclusions and dropouts or background factors of patients. 2) The efficacy rate determined by the committee was 73.3% in the NY-198 group and 70.8% in the CCL group with no significant difference between the two groups. As for the bacteriological effiect, the elimination rate of organisms was 78.3%(54/69 isolates) in the NY-198 group and 61.8%(42/58 isolates) in the CCL group, with a significant difference (p=0.041). 3) There were no significant differences between the two groups with respect to the degree of improvement in various symptoms, signs and laboratory findings. 4) Side effects were observed in 12 patients (7.2%) of the NY-198 group and 10 (6.0%) of the CCL group, and abnormal changes in laboratory findings in 21 patients (13.5%) of the NY-198 group and 23 (15.4%) of the CCL group, with no significant difference in incidence. 5) The utility rate (satisfaction rate) calculated by the committee was 68.4% in the NY-198 group and 67.1% in the CCL group, with no significant difference between the two groups. The above results indicate that NY-198 in daily doses of 600 mg is as useful as CCL in daily doses of 1, 500 mg. Especially against Gram-negative bacteria, NY-198 has a higher elimination rate than CCL in the treatment of respiratory tract infections (pneumonia and chronic respiratory infection).
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