Question 1
Which of the following representsthe major route of metabolism for acetaminophen?
- AOption A:
Glucuronidation
- BOption B:
Sulfation
- COption C:
Cytochrome P-450 oxidation
- DOption D:
Direct renal excretion
- EOption E:
Plasma breakdown
Show answer and explanation
Correct answer: A
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.