Very short DOA of 3% 2-chloroprocaine is due to metabolism by which enzyme?

Very short DOA of 3% 2-chloroprocaine is due to metabolism by which enzyme?

• A. Acetylcholinesterase
• B. Butyrylcholinesterase
• C. Esterase
• D. Monoamine oxidase

Answer: (C)

Very short durations for ester-type local anesthetics come from rapid inactivation by esterase enzymes in the blood. 2-chloroprocaine is an ester; once it enters circulation, plasma esterases quickly hydrolyze it to inactive metabolites, so it loses effect almost immediately. Among cholinesterases, this hydrolysis is carried out by plasma esterases (a form of butyrylcholinesterase), which is why the broad category “esterase” best explains the rapid metabolism. Acetylcholinesterase acts mainly at cholinergic synapses and isn’t the primary route for hydrolysis of ester local anesthetics in plasma, and monoamine oxidase handles amines rather than esters.

Very short durations for ester-type local anesthetics come from rapid inactivation by esterase enzymes in the blood. 2-chloroprocaine is an ester; once it enters circulation, plasma esterases quickly hydrolyze it to inactive metabolites, so it loses effect almost immediately. Among cholinesterases, this hydrolysis is carried out by plasma esterases (a form of butyrylcholinesterase), which is why the broad category “esterase” best explains the rapid metabolism. Acetylcholinesterase acts mainly at cholinergic synapses and isn’t the primary route for hydrolysis of ester local anesthetics in plasma, and monoamine oxidase handles amines rather than esters.