Ritipenem is a synthetic b-lactam antibiotic of the penem class that has a broad antimicrobial spectrum and high resistance to b-lactamases. Since it is stable in relation to renal dehydropeptidase-I, ritipenem does not require concomitant administration of an inhibitor of this enzyme.
Uses
Ritipenem is a penem antibiotic.
Mechanism of action
In common with other b-lactams, ritipenem interacts with the penicillin-binding proteins (PBPs). In E. coli, the main target of ritipenem is PBP2, and PBP3 is also equivalent to PBP2 in the Enterobacteriaceae. In vitro studies suggest that ritipenem has affinity for the PBP2 of methicillin-susceptible S. aureus and PBP2u of methicillin-resistant S. aureus.
Clinical Use
Ritipenem has been used in a limited number of clinical conditions in which the use of a carbapenem that can be administered both parenterally and orally was considered a possible advantage. Ritipenem is not currently licensed for clinical use by the US FDA. Only a few clinical studies have assessed the role of ritipenem therapy, and these have been in the treatment of respiratory tract or urinary tract infections, but results appear generally disappointing.
Toxicology
In an Italian study, 8 of 15 (53%) chronic obstructive pulmonary disease (COPD) patients treated with 3.0 g of ritipenem acoxil developed mild to severe gastrointestinal complaints (diarrhea). Few other toxicity data are currently available.
