Acetaminophen
- Class: Analgesic / antipyretic
- Used for: pain and fever
- Say it: uh-see-tuh-MIN-oh-fen
- Forms: tablet, capsule, oral liquid, suppository, injection
Remember the name – ACETA → a-SET-a, the set-point
ACETAMINOPHEN RESETS the body's thermostat. The fever comes down and the pain fades — but the swelling does not.
It works centrally on the hypothalamic set-point, with almost no anti-inflammatory action in the tissues. That is the one fact that separates it from every NSAID.
ACETAMINOPHEN RESETS the body's thermostat. The fever comes down and the pain fades — but the swelling does not.
It works centrally on the hypothalamic set-point, with almost no anti-inflammatory action in the tissues. That is the one fact that separates it from every NSAID.
Mnemonic: Acetaminophen: pain and pyrexia only
It is not an NSAID. It barely touches inflammation, spares the stomach lining and leaves platelets alone — which is why it is the safe default. The trade-off is entirely in the liver.
It is not an NSAID. It barely touches inflammation, spares the stomach lining and leaves platelets alone — which is why it is the safe default. The trade-off is entirely in the liver.
Side effects
Common: few at normal doses
Serious: liver failure in overdose
Typical dose
500–1000 mg every 4–6 hours; maximum 4 g daily
That 4 g ceiling is the entire safety margin. Lower it to 3 g in the frail, underweight or in liver disease, and count every combination product.
Check yourself
What is the main danger of an acetaminophen overdose?
- Liver failure
- Bleeding from the stomach
- Kidney stones
- Dangerous bleeding from blocked platelets
Show answer
A. Liver failure
At normal doses the toxic metabolite is mopped up by glutathione. In overdose those stores run out and the metabolite attacks liver cells — often with no symptoms at all for the first day.
See it, don't memorize it
The app has the mechanism comic and a patient case for Acetaminophen – plus the name link, the class mnemonic, pronunciation you can hear, and a self-check, for the top 100 drugs. One purchase, no subscription, no account.