What is the maximum recommended daily dose of acetaminophen for a healthy adult?

• A. 3000 mg
• B. 4000 mg
• C. 5000 mg
• D. 6000 mg

Answer: (B)

The key idea is balancing pain relief with the risk of liver injury from acetaminophen. In the liver, most of the drug is processed safely, but a small amount is converted to a toxic metabolite (NAPQI). Normally glutathione detoxifies this, but when intake is too high, glutathione is depleted and NAPQI can damage liver cells. For a healthy adult, the safest upper limit is 4000 mg (4 grams) in 24 hours. This is usually taken as up to about 650 mg every 4–6 hours, not to exceed four doses in a day. Doses higher than 4000 mg daily significantly raise the risk of serious liver injury, especially with factors like alcohol use, fasting, or existing liver disease. The other options exceed or approach unsafe levels, so the 4000 mg daily limit is the best answer.