Amides are primarily metabolized in which organ?

Amides are primarily metabolized in the liver due to the presence of liver enzymes that effectively break down these compounds. The metabolism of amides involves hepatic microsomal enzymes, which are part of the cytochrome P450 system. These enzymes convert amide local anesthetics into more water-soluble metabolites that can be easily excreted by the kidneys.

Unlike esters, which are metabolized by plasma enzymes, amides' metabolic pathway is more complex and requires the liver for their breakdown. This characteristic is crucial for understanding how the duration and potency of amide local anesthetics can vary based on liver function and overall metabolism.

Other organs mentioned, such as the heart and kidneys, do not play a primary role in the metabolism of amides. Instead, the heart is involved in the circulation and potential systemic effects of the anesthetic, while kidneys are primarily responsible for excreting the metabolites after they have been processed by the liver. Plasma is involved in the initial distribution of the drug but does not metabolize amides.