Which Carbapenem is noted for requiring co-administration with Cilastin?

The correct answer is Imipenem, as it is the only carbapenem that requires co-administration with cilastatin to enhance its effectiveness and reduce its nephrotoxic potential. Cilastatin acts as a renal dehydropeptidase inhibitor, preventing the rapid breakdown of imipenem in the kidneys. Without cilastatin, imipenem is significantly inactivated by this enzyme, which can lead to suboptimal therapeutic levels and increased risk of kidney damage due to its metabolites.

On the other hand, the other carbapenems listed, such as Meropenem, Ertapenem, and Doripenem, do not require cilastatin for their activity and stability. They are resistant to the renal dehydropeptidase and can be administered independently, making the combination unnecessary for those specific drugs. This distinction illustrates the unique pharmacological characteristic of imipenem among the carbapenem class.