Ester vs Amide LA — NDEB AFK MCQ
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Correct answer: B — Benzocaine
Benzocaine is an ester-type local anaesthetic (along with procaine, tetracaine, and cocaine). All commonly used injectable dental local anaesthetics (lidocaine, mepivacaine, prilocaine, bupivacaine, articaine) are amides. The key difference: esters are metabolised by plasma pseudocholinesterase (rapid degradation, more allergenic due to PABA metabolite); amides are metabolised by hepatic microsomal enzymes (slower metabolism, very rare true allergic reactions). Articaine has both an amide bond AND an ester group (making it partially metabolised by esterases), which is unique.
Reference: Malamed – Handbook of Local Anesthesia, 7th ed., 2020