Pharmacology · single question
Which class of local anesthetics is associated with methemoglobinemia?
Show answer and explanation
Correct answer: A. Esters (benzocaine, procaine)
ESTER-type local anesthetics (benzocaine, procaine) metabolize to PABA derivatives that oxidize Hgb Fe2+ → Fe3+ (methemoglobin). Prilocaine (amide) also causes methemoglobinemia via similar metabolite (toluidine). Symptoms: cyanosis, chocolate-colored blood. Treatment: methylene blue.