Which of the following represents the major route of metabolism for acetaminophen?

Which of the following represents the major route of metabolism for acetaminophen?
A . Glucuronidation
B . Sulfation
C . Cytochrome P-450 oxidation
D . Direct renal excretion
E . Plasma breakdown

View Answer

Answer: A

Explanation:

Acetaminophen is metabolized by choices A through D. The major route is glucuronidation catalyzed by UDP-glucuronyl transferase in the liver. Sulfation is the next most common route and is the target mechanism for NAC therapy. Oxidation by cytochrome P-450 results in the formation of N-acetyl-p­benzoquinone imine, which is responsible for the hepatic necrosis caused by acetaminophen overdose. Direct renal excretion represents approximately 5% of the metabolism of acetaminophen. Plasma metabolism of acetaminophen does not generally occur.