Which type of local anesthetic is less likely to cause allergic reactions?

Amide-type local anesthetics are less likely to cause allergic reactions compared to ester-type local anesthetics due to their chemical structure and metabolism. Esters are metabolized by plasma pseudocholinesterase, leading to the formation of para-aminobenzoic acid (PABA), a compound that is known to cause allergic reactions in some patients. This reaction is thought to be related to the body’s immune response to PABA.

In contrast, amide-type local anesthetics are metabolized in the liver, and do not produce PABA or similar compounds that can trigger allergic responses. Consequently, while both types of anesthetics can cause adverse effects, the incidence of true allergic reactions is much higher with ester-type agents. Thus, when considering which type of local anesthetic is less likely to cause such reactions, amide-type local anesthetics are favored.