Benzocaine is an example of which type of local anesthetic?

• A. Ester
• B. Amide
• C. Ester and Amide
• D. Cocaine derivative

Answer: (A)

Local anesthetics are grouped by the chemical bond that links the aromatic ring to the amine: ester or amide. Benzocaine is the ethyl ester of p-aminobenzoic acid, so it contains an ester linkage. Esters are quickly broken down by plasma esterases, which gives them a shorter duration of action and makes them well-suited for topical or surface anesthesia. This contrasts with amide local anesthetics, which have a more stable amide bond, are often metabolized in the liver, and generally provide longer-lasting effects. Benzocaine’s ester structure is also why it’s used mainly for topical mucosal anesthesia rather than as a long-acting injectable. It is not a cocaine derivative, and its classification is specifically as an ester local anesthetic.