Which local anesthetic is commonly associated with causing allergic reactions?

Procaine is the local anesthetic commonly associated with causing allergic reactions due to its chemical structure, which can provoke hypersensitivity responses in some individuals. It is an ester local anesthetic, and esters are known to be more likely to cause allergic reactions compared to amide local anesthetics. The metabolism of procaine produces para-aminobenzoic acid (PABA), which is a compound known to sensitize some patients, potentially leading to allergic responses.

In contrast, lidocaine, bupivacaine, and articaine are amide local anesthetics, which generally have a lower incidence of allergic reactions. The allergic responses attributed to these agents are quite rare and typically occur due to preservatives or other components in the formulation rather than the anesthetic itself. Understanding the differences in chemical structures and the susceptibility of esters versus amides to cause allergic reactions can be crucial for clinicians when selecting the appropriate local anesthetic for their patients.