General Principles

Imipenem–cilastatin (500 mg–1 g IV/IM q6–8h), meropenem (1–2 g IV q8h or 500 mg IV q6h), and ertapenem (1 g IV q24h) are the currently available carbapenems in the United States. Carbapenems exert their bactericidal effect by interfering with cell wall synthesis, similar to PCNs and cephalosporins, and are active against many gram-positive and most gram-negative bacteria, including anaerobes. They are among the antibiotics of choice for infections caused by organisms producing AmpC or ESBLs. Imipenem–cilastatin is the most active carbapenem against ampicillin-susceptible E. faecalis and can also be used for treating Nocardia and some atypical mycobacterial infections.