Ertapenem is another synthetic carbapenem with a rather complex side chain at C-3. It is used once daily
parenterally, with special application against anaerobes. As with meropenem, the 4-β-methyl group confers
stability toward dehydropeptidase-1 It is not active against pseudomonads or acinetobacteria and, therefore,
should not be substituted for imipenem or meropenem. It is relatively strongly bound to serum proteins, so it
has a prolonged half-life, making it more convenient to use than the other carbapenems when its spectrum
warrants this. Its reported indications include complicated intra-abdominal and complicated skin/skin
structure infections caused by sensitive organisms (for intra-abdominal: Escheri chia coli, Clostri di um
clostri doforme, Bacteroi des fragilis, and Peptostreptococcus sp; for skin/skin structures: Staphylococcus
aureus (methicillin-susceptible strains), Streptococcus pyogenes, E.coli, or Peptostreptococcus sp.). It can
be administered once daily.
