Which local anesthetic class is metabolized by plasma esterases?

The correct choice is based on the metabolic pathways of local anesthetics. Ester class local anesthetics are primarily metabolized by plasma esterases, which are enzymes found in the blood. This metabolic process involves the enzymatic breakdown of the ester bonds in the anesthetic molecules. Examples of ester local anesthetics include procaine and cocaine, which are rapidly hydrolyzed in the plasma, leading to a shorter duration of action compared to their amide counterparts.

In contrast, amide local anesthetics, such as lidocaine and bupivacaine, undergo metabolism primarily in the liver via hepatic enzymes rather than in the plasma. This distinction is critical in understanding the pharmacokinetics of local anesthetics, as it leads to differences in efficacy, duration of action, and potential side effects.

This knowledge is essential for clinicians when considering the appropriate use of local anesthetics in various medical procedures, as the metabolic pathway can influence the choice of anesthetic based on patient factors and the desired duration of anesthesia.