Synonyms: Paracetamol

Medical Specialties: Family practice, Internal medicine, Pediatrics

Clinical Definition

Acetaminophen is a crystalline compound classified as a non-opioid analgesic. It is also used as an antipyretic with a similar potency to aspirin. The exact mechanism of action of acetaminophen is not clear, but it does appear to inhibit the synthesis of prostaglandins. In large doses, acetaminophen can lead to acute hepatic toxicity.

In Our Own Words

Acetaminophen is an ingredient in many nonprescription drugs used to reduce fevers and treat pain. When dosed correctly, there are usually very few side effects. Acetaminophen is found in many different medications and formulations sold over the counter and at drug stores, so using the correct dose is important.


Acetaminophen may reduce pain by blocking pain signals in the body – signals that chemicals called prostaglandins play a part in sending. Acetaminophen blocks some of the actions of prostaglandins, helping with pain, and is considered well tolerated, but if it is taken in higher than recommended doses, whether accidentally or in hopes of a better effect, it can lead to liver damage.

Relevant Conditions
  • Fever
  • Headaches
  • Menstrual periods
  • Aches and moderate pain
Side Effects
  • Nausea
  • Liver damage (chronic use; improper dosage)
Share this article
  • McNicol, Evan. “Ask the Professor.” Tuffs Journal. 2008. Accessed October 2013.
  • Devlin, Thomas M., ed. Textbook of Biochemistry: With Clinical Correlations. 5th edition. Wiley-Liss. 2002. Accessed October 2013.
  • Committee on Drugs. “Acetaminophen Toxicity in Children.” 108(4) Journal of the American Academy of Pediatrics. 2001 Accessed October 2013.
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