Which organ is primarily affected by drug-induced liver injury?

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

Answer: (A)

Drug-induced liver injury happens because the liver is the main organ responsible for drug metabolism and detoxification. After a drug is absorbed, it largely passes through the liver via the portal circulation, where enzymes—especially cytochrome P450s—transform it. This metabolic processing can produce reactive intermediates that damage hepatocytes or disrupt bile flow, leading to hepatocellular injury or cholestasis. Clinically, this shows up as elevated liver enzymes (like ALT and AST) and sometimes alkaline phosphatase or bilirubin, depending on the injury pattern. While the kidneys, heart, or lungs can be affected by certain drugs or systemic toxicity, the liver is the primary organ impacted in drug-induced liver injury.