Carbapenem

Carbapenems are a class of beta-lactam antibiotics with a broad spectrum of antibacterial activity, and have a structure which renders them highly resistant to beta-lactamases. Carbapenem antibiotics were originally developed from thienamycin, a naturally-derived product of Streptomyces cattleya.^[1]

The following drugs belong to the carbapenem class:

• Imipenem (often given as part of Imipenem/cilastatin)
  • Imipenem can be hydrolysed in the mammalian kidney by a dehydropeptidase enzyme, and so is given with a dehydropeptidase inhibitor, cilastatin
• Meropenem
• Ertapenem
• Faropenem
• Doripenem
• Panipenem/betamipron

These agents have the broadest antibacterial spectrum compared to other beta-lactam classes such as penicillins and cephalosporins. Additionally they are generally resistant to the typical bacterial beta-lactamase enzymes which are one of the principal resistance mechanisms of bacteria. They are active against both Gram positive and gram negative bacteria, with the exception of intracellular bacteria, such as the Chlamydiae.

The carbapenems are structurally very similar to the penicillins, but the sulfur atom in position 1 of the structure has been replaced with a carbon atom, and hence the name of the group, the carbapenems.

Due to their expanded spectra, the desire to avoid generation of resistance and the fact that they have generally poor oral bioavailability, they are administered intravenously in hospital settings for more serious infections. However, research is underway to develop an effective oral carbapenem.^[2]