Cethromycin: a promising new ketolide antibiotic for respiratory infections.

Community-acquired pneumonia remains the primary infectious cause of death in the United States. At current levels of antimicrobial resistance, conventional agents are at risk of becoming less effective, and the need for new agents is pressing. Cethromycin is a new ketolide antibiotic being investigated for use in respiratory tract infections. To review its pharmacology, in vitro susceptibilities, pharmacokinetics, efficacy, safety, and drug interactions, we conducted a MEDLINE search restricted to English-language articles citing cethromycin or ABT-773 (its original designation) from 1990-May 2009. Additional data sources were identified from the references of selected articles. All published trials and available poster data citing cethromycin were selected for review. In vitro, cethromycin displays more potent antibacterial effects than its predecessor telithromycin. Cethromycin exhibits potent inhibition of both gram-positive and gram-negative respiratory pathogens. A new drug application for cethromycin was submitted to the United States Food and Drug Administration in 2008 for the treatment of community-acquired pneumonia. Clinical trial data in the treatment of respiratory tract infections support cethromycin's efficacy. The limited safety data have not included any reports of hepatotoxicity. If cethromycin proves to be safe with regard to hepatotoxicity, it has great promise as an alternative to current standard therapy for community-acquired respiratory infections, especially pneumonia. Given current resistance levels, cethromycin could provide more reliable coverage against common respiratory pathogens than traditional agents in the beta-lactam and macrolide classes.