Meropenem: a new carbapenem antimicrobial

To describe and then compare an investigational carbapenem antibiotic, meropenem, with the only currently available antibiotic in this class, imipenem/cilastatin.

An English language search using MEDLINE (1988-1993); Abstracts of the 31st Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), 1991; and Abstracts of the 32nd ICAAC, 1992.

All current scientific publications were reviewed for study design and quality. Emphasis was placed on susceptibility and pharmacokinetic analysis. Phase 3 clinical trials are now being completed and have only been published in abstract form. Hence, conclusions derived regarding efficacy were tempered.

Meropenem is active against a broad spectrum of gram-positive and -negative pathogens including beta-lactamase producers. Meropenem appears to be two- to fourfold less active than imipenem against gram-positive organisms. Meropenem is two- to fivefold more active against enterobacteriaceae. The two compounds appear to be equally active against Pseudomonas aeruginosa. Pharmacokinetic disposition is also similar for imipenem and meropenem. Meropenem may exhibit greater tissue penetration. Meropenem is not labile to renal hydrolysis and can be administered without a competitive antagonist of dihydropeptidase, such as cilastatin. In clinical trials, meropenem appears to be as safe and effective as imipenem/cilastatin or ceftazidime in the treatment of infections involving soft tissue, urinary tract, upper respiratory tract, abdominal processes, and febrile neutropenic episodes.

Meropenem is comparable to imipenem in terms of in vitro susceptibility pattern and pharmacokinetic disposition. Overall, meropenem seems to offer promise as the second of the carbapenem class of antibiotics. Clinical data are preliminary, and further data are needed.