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How Does Acetaminophen Work?: Detailed Datasheet

Medically reviewed by Min Clinic Staff | Updated: January 2026

How does acetaminophen work?

Acetaminophen is an analgesic and antipyretic drug which is used to relieve pain and fever. Acetaminophen blocks pain by inhibiting the synthesis of prostaglandin, a natural substance in the body that initiates inflammation. Acetaminophen reduces fever by acting on the hypothalamus region of the brain which regulates temperature.

How is acetaminophen used?

Acetaminophen is administered through the following routes for relief of mild to moderate pain and fever:

  • Rectal: Acetaminophen may be administered as a suppository inserted into the rectum for patients who are unable to take it orally.
  • Oral: Oral acetaminophen comes in several forms such as tablets for swallowing, chewable or disintegrating tablets, capsules, syrups and solutions.
  • Intravenous: IV acetaminophen is usually administered in hospital settings to achieve rapid pain control.

What are side effects of acetaminophen?

Side effects of acetaminophen may include:

Acetaminophen rectal

Acetaminophen oral

Acetaminophen IV

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

What are names of some acetaminophen drugs?

Generic and brand names of acetaminophen include:

  • acetaminophen
  • acetaminophen IV
  • acetaminophen rectal
  • Adults' FeverAll
  • FeverAll
  • FeverAll Infants
  • FeverAll Junior Strength
  • Little Fevers Children's Fever/Pain Reliever
  • Little Fevers Infant Fever/Pain Reliever
  • Ofirmev
  • PediaCare Single Dose Acetaminophen Fever Reducer/Pain Reliever
  • Tylenol
  • Tylenol Arthritis Pain
  • Tylenol Ext