Acetaminophen is toxic to which organ?

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

Answer: (B)

The main idea is how acetaminophen is processed in the body and how toxicity develops. At normal doses, acetaminophen is safely metabolized in the liver and excreted. When taken in excess, a portion is converted by liver enzymes into a reactive metabolite called NAPQI. This metabolite is normally neutralized by glutathione, but in overdose or when glutathione is depleted, NAPQI damages liver cells, leading to hepatocellular injury and potential liver failure. Because the liver handles drug metabolism and is where this toxic metabolite accumulates, it is the organ most affected. The heart, kidneys, and lungs can be impacted in other toxic scenarios, but the classic organ targeted by acetaminophen toxicity is the liver. If overdose is suspected, treatment with N-acetylcysteine helps replenish glutathione and reduce liver injury.