Which organ is the primary site for metabolism of amide local anesthetics?

Which organ is the primary site for metabolism of amide local anesthetics?

• A. Liver
• B. Kidney
• C. Lungs
• D. Spleen

Answer: (A)

Amide local anesthetics are broken down mainly in the liver by hepatic enzymes (amidases and related CYP pathways). The liver’s high blood flow and enzyme content make it the primary site for converting these drugs into inactive metabolites, and hepatic impairment slows their metabolism, lengthening their effects. The kidneys mainly handle excretion of metabolites, not metabolism; the lungs can contribute a smaller amount of metabolism for some agents like lidocaine, but not as the main site; the spleen isn’t a significant player. So the liver is the principal site of metabolism for amide local anesthetics.

Amide local anesthetics are broken down mainly in the liver by hepatic enzymes (amidases and related CYP pathways). The liver’s high blood flow and enzyme content make it the primary site for converting these drugs into inactive metabolites, and hepatic impairment slows their metabolism, lengthening their effects. The kidneys mainly handle excretion of metabolites, not metabolism; the lungs can contribute a smaller amount of metabolism for some agents like lidocaine, but not as the main site; the spleen isn’t a significant player. So the liver is the principal site of metabolism for amide local anesthetics.