Comparison of Four Carbapenems; Imipenem-Cilastatin, Panipenem-Betamipron, Meropenem, and Biapenem with Review of Clinical Trials in Japan

The development of carbapenem gives a revolutionary impact to the chemotherapy of infectious diseases. The bacteriological and clinical efficacies of carbapenems, including imipenem/cilastatin, panipenem/betamipron, meropenem and biapenem, were evaluated. All four carbapenems were potent against gram-positive and gram-negative bacteria except Stenotrophomonas maltophilia. The antimicrobial activities of meropenem against Enterobacteriaceae were slightly superior to other carbapenems. Imipenem and panipenem were slightly more active against gram-positive bacteria than meropenem and biapenem. Biapenem was the most potent against Acinetobacter anitratus. The in vitro activity of imipenem was compared between 1990 and 1992 in Nagasaki University Hospital. The resistance rate of S. aureus, whose MIC is higher than 25 mg/l, increased from 3% to 22%, S. pneumoniae, whose MIC is higher than 0.05 mg/l, increased from 9% to 30% and P. aeruginosa, whose MIC is higher than 5 mg/l, increased from 20% to 32%. The isolation rates of S. maltophilia from sputum increased gradually from 0.9% in 1984 to 3.5% in 1991. The clinical efficacy rates of imipenem/cilastatin and panipenem/betamipron were 79% and 77%, and the rates of meropenem and biapenem 100% and 96.2% for the treatment of respiratory infection in our department, respectively. The efficacy rates of imipenem/cilastatin decreased from 79% to 67.7% after being commercialized. This decline was due to administration to patients with severe underlying diseases and with infection caused by resistant strains such as P. aeruginosa and S. aureus. The phase II and III trials of carbapenems in internal medicine, which were performed separately in Japan, showed that the clinical efficacy rates were 73%, 79%, 86% and 89%, and the rates of adverse reaction were 4.7%, 3.3%, 1.8% and 2.2% in imipenem /cilastatin, panipenembetamipron, meropenem and biapenem, respectively. Newly develope