Imipenem/cilastatin sodium and other beta-lactams for respiratory tract infections: clinical benefit and treatment days for cure]

Therapeutic efficacy and the treatment days for cure of imipenem/cilastatin sodium (IPM/CS) in treatment of pulmonary infections were prospectively determined in comparison with those of beta-lactams other than carbapenems mainly ceftazidime (CAZ) or sulbactam/cefoperazone (SBT/CPZ). The overall response rate was 84.9% (62/73) in the IPM/CS group and 74.7% (56/75) in the beta-lactam group, the difference not being significant. In the subjects having underlying respiratory diseases, the response rate was 91.1% (41/45) and 73.9% (34/46) in the IPM/CS and beta-lactam groups, respectively. In patients with infections secondary to chronic respiratory disease, the rate was 91.2% (31/34) in the former group and 66.7% (24/36) in the latter group, respectively. The differences were significant for both stratified analyses. The treatment days for cure judged by the attending physician were 12.9 +/- 0.6 days in the IPM/CS group, and 14.5 +/- 0.7 days in the beta-lactam group. The difference was not, however, significant. In patients with mild to moderate infections, the treatment days for cure was 12.0 +/- 0.6 days (n = 64) in the IPM/CS group and 14.3 +/- 0.7 days (n = 70) in the beta-lactam group. In patients with underlying respiratory disease, the treatment days for cure were 11.8 +/- 0.7 days (n = 45) and 14.7 +/- 0.9 days (n = 46) in the IPM/CS and beta-lactam groups, respectively. In patients with infections secondary to chronic respiratory disease, the days were 11.1 +/- 0.7 days (n = 34) and 14.7 +/- 1.1 days (n = 36), respectively. Thus, IPM/CS therapy significantly reduced the number of treatment days until cure. There was, however, no significant difference between the two therapy groups in treatment of the patients with severe infections, those without underlying respiratory disease, or those with pneumonia and/or lung abscess. The treatment days for cure were also assessed by the members of review committee taking into consideration of body temperature, leukocyte count, and C-reactive protein. As the result, it was 6.9 +/- 0.5 days in the IPM/ CS and 10.3 +/- 0.7 days in the beta-lactam groups; respectively, and the difference was significant. Time (days) until cure was also compared between the two groups using survival time analysis, confirming a more rapid response in the IPM/CS group. Although IPM/CS therapy was associated with a shorter response time as assessed by both the attending physicians and the review committee, there were considerable differences between the results of these judgements. Thus, the duration of treatment with injectable antibiotics requires reevaluation in the future. No significant differences were observed between the groups with respect to parameters indicating side effects and laboratory abnormalities. There were no severe symptoms or laboratory findings, and symptoms and changes in laboratory values, if any resolved during the course of therapy or after the withdrawal of treatment. In conclusion, IPM/CS seems to be very useful as first-line therapy for respiratory tract infections and for shortening the duration of treatment.