What is acetaminophen?

Acetaminophen is an active ingredient that relieves pain and reduces fever. It is available in over-the-counter and prescription medications. Acetaminophen is also combined with other ingredients in medicine that treats the flu, coughs and colds.

How it works

The exact way acetaminophen works to relieve pain is unknown. It is believed to block the production of an enzyme in the brain that is related to pain. Similarly, it is thought to work on the brain mechanism that elevates body temperature.

What does acetaminophen treat?

Acetaminophen is used to treat mild to moderate pain and reduce fever. Pain that may be treated includes, but is not limited to, the following:

  • Headache
  • Muscle ache
  • Menstrual cramp
  • Dental pain
  • Colds
  • Sore throat
  • Backache
  • Pain related to vaccinations
  • Osteoarthritis


Acetaminophen is available in tablets, chewable tablets, capsules, liquid, extended-release, and quick-dissolving tablets. It can be taken orally, with or without food.

Acetaminophen should be taken directly as instructed. Extended-release tablets should not be chewed or crushed. Adults should not take longer than 10 days, and children should not take longer than five days, unless directed by a health care professional. The maximum recommended dose for adults is 4,000 mg per day. Higher than the recommended doses may cause liver damage.

Side effects

Acetaminophen typically has no side effects. Seek immediate medical assistance if an allergic reaction is suspected. This includes trouble breathing, dizziness, rash, itching, or swelling of the tongue, throat, mouth or face. Contact a health care professional or pharmacist if other, but less serious, side effects occur.


Acetaminophen is often included as an ingredient in other medications; therefore, use caution to avoid going over the daily maximum dose. Talk to a health care professional before taking acetaminophen if liver disease or regular use of alcohol is present. This medication may contain sugar; therefore, those with diabetes or phenylketonuria (PKU) should be mindful.

Those pregnant or planning to become pregnant should consult with a medical professional prior to taking this medicine. Acetaminophen also passes through breast milk. Drug interactions can occur, so disclose any over-the-counter or prescription medications, supplements, vitamins or herbs that are being taken. Store at room temperature away from light, moisture, children and pets.

Additional source: Tufts University School of Medicine

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