Acetaminophen

Drug Name
Acetaminophen

Brand Name(s)
Tylenol®, Tylenol Arthritis®, Tylenol® Muscle Aches and Body Pain, etc.

Drug Class
Non-prescription medication

Acetaminophen is used to treat pain associated with osteoarthritis and, sometimes, inflammatory forms of arthritis.

  • What types of arthritis are acetaminophen used for?

    Acetaminophen is used to treat pain associated with osteoarthritis and, sometimes, inflammatory forms of arthritis.

  • How is acetaminophen administered?

    Acetaminophen is typically taken orally.

  • What is the typical dose and when do I take it?

    The typical dose of acetaminophen is 325 mg to 1,000 mg every four to six hours. The maximum daily dose is four grams (4,000 mg).

    • Regular Strength tablets (325 mg each): One to two tablets every four to six hours to a maximum of 12 tablets per day.
    • Extra Strength tablets (500 mg each): One to two tablets every four to six hours to a maximum of eight tablets per day.
    • Extended Release tablets (650 mg each) (i.e., Tylenol® Arthritis, Tylenol® Muscle Aches and Body Pain): One tablet every eight hours to a maximum of six tablets per day.
  • How long will it take to work?

    Acetaminophen typically begins to take effect within one to two hours.

  • When should I not take acetaminophen and call my doctor?

    Ask a doctor or pharmacist before use if you have serious liver or kidney disease or chronic alcohol use (three or more drinks per day). Do not take acetaminophen if you have an allergy to acetaminophen. 

    Taking more than the recommended maximum daily amount of acetaminophen can be dangerous. If you have consumed more than the recommended amount, please contact your health-care provider immediately, even if you do not notice any possible signs or symptoms of excess use, such as increased sweating, nausea, vomiting, stomach pain and loss of appetite. 

    Acetaminophen, when taken daily, may interact with warfarin. If you take warfarin for another medical condition, please speak to a health-care provider before starting regular acetaminophen.

  • What are the side effects of acetaminophen?

    Although acetaminophen is one of the safest medications for treating pain and is generally well tolerated, long-term use carries a low, but dangerous, risk of liver damage and possible kidney damage.

  • What helps to reduce side effects?

    Do not exceed the maximum daily dose of acetaminophen. Acetaminophen is found in a number of other over-the-counter medications, such as cough and cold products and prescription medications for pain relief. Carefully look at the ingredients of all the over-the-counter medications and prescription medications you are taking to ensure you are not taking too much acetaminophen. Consult your pharmacist if you have questions about the amount of acetaminophen in over-the-counter products.

    Avoid regular consumption of alcohol while taking acetaminophen as it can increase the risk of liver toxicity. Consuming more than three alcoholic drinks per day may increase the risk of liver damage.

  • Do I need any monitoring while taking acetaminophen?

    Routine blood tests or monitoring are not normally required while you are taking acetaminophen. Your health-care provider may meet with you regularly to ensure that acetaminophen is adequately controlling your pain.


This information was last updated November 2017, with expert advice from:

Jason Kielly, B.Sc. (pharm.), Pharm.D.
Assistant Professor, School of Pharmacy, Memorial University of Newfoundland
Clinical Pharmacist, Rheumatic Health Program, Eastern Health

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