Doripenem (doribax), a new carbapenem antibacterial agent.

134 P&T® • March 2008 • Vol. 33 No. 3 INTRODUCTION Carbapenems represent a class of beta-lactam antibacterial agents with a broad spectrum of activity against grampositive, gram-negative, and anaerobic bacteria. This class is bactericidal in nature, but it does not cover species of Enterococcus faecium, methicillin-resistant Staphylococcus aureus (MRSA), or Stenotrophomonas maltophilia. Collectively, the carbapenems have been used to treat a variety of infections. As with all antibiotics, resistance within the carbapenem class is a major concern. Although carbapenems remain the drugs of choice for extended-spectrum, beta-lactamase–producing organisms, resistance may emerge via other betalactamases, such as metallo–betalac tamases, alteration of porin channels, or up-regulation of efflux pumps. Therefore, carbapenems should be used judiciously, and the appropriate use of these agents must be considered carefully. The Food and Drug Administration (FDA) has approved four carbapenems: