OTC Pain Relief: Understanding Acetaminophen

Medically Reviewed by Michael W. Smith, MD on September 16, 2011
4 min read

You’ve probably taken acetaminophen at one time or another for fever or pain relief. You may know acetaminophen as the active ingredient in Tylenol and many other over-the-counter (OTC) products, including cold medications.

When used as directed, taking acetaminophen is generally safe and effective. But it can be harmful if it’s not taken correctly. Read on to learn about the benefits and risks of acetaminophen and how to use it safely.

Acetaminophen is the most commonly used medicine for pain relief in the United States. For most people, when used as directed, it safely reduces fever and relieves many kinds of mild to moderate pain -- from backaches, headaches, and sprains to arthritis and menstrual cramps. And when it’s taken correctly, side effects are rare.

Another benefit of acetaminophen is that it doesn’t cause stomach upset or heart problems -- both possible risks with the other major type of OTC pain relievers, called nonsteroidal anti-inflammatory drugs (NSAIDs).

“Acetaminophen may be a good alternative for pain relief for those who are at risk of heart disease or stomach problems with NSAIDs,” says Elliott Antman, MD, professor of medicine at Harvard Medical School and Brigham and Woman’s Hospital in Boston.

“Acetaminophen is considered to be safe and effective in the recommended doses, according to the ‘Drug Facts’ label,” says Joel Schiffenbauer, MD, deputy director of nonprescription clinical evaluations at the FDA Center for Drug Evaluation and Research.

The Drug Facts label is found on the package of every OTC medicine. It lists the active ingredients, how to take the medicine, what it is supposed to do, and any warnings about its use.

When taken incorrectly, however, acetaminophen can cause liver damage. And your risk of liver damage may be increased if you drink more than three alcoholic drinks every day, take more than the recommended dose (overdose), or if you take any additional drugs that also contain acetaminophen at the same time.

When taking acetaminophen, follow these tips:

  • For some health conditions, talk with your doctor first. Ask your doctor about taking acetaminophen if you have liver disease or have three or more alcoholic drinks a day. If you’re at higher risk for liver damage from acetaminophen -- even at the recommended dose -- your doctor may advise you not to take it.
  • Take it as directed. Take acetaminophen as instructed on the Drug Facts label or follow your doctor’s instructions very carefully. Don't take it for longer than 10 days without checking with your doctor.
  • Make sure to use the correct dosage. Don’t take more acetaminophen than directed or take it more often than directed. Taking more than recommended can damage your liver -- and won’t provide any more pain relief.

“Consumers taking any OTC pain reliever who find the dose in the Drug Facts label is not adequate to control their symptoms should seek medical advice,” says Schiffenbauer.

  • Don’t take other medications with acetaminophen. Read labels carefully so you don’t take more than one medicine that contains acetaminophen at a time. Acetaminophen is an active ingredient in more than 600 different OTC and prescription medicines, including pain medications, fever reducers, and cold and flu symptom remedies.
  • Be aware of acetaminophen’s other names. On some prescription labels, acetaminophen may be listed as “APAP.” Outside of the United States, it is often called paracetamol.
  • Tell your doctor if you take Coumadin. Ask your doctor before using acetaminophen if you also take warfarin (Coumadin), as it may increase the risk of bleeding.

Acetaminophen is used in many OTC medicines to treat fever and pain in children. Because children are also at risk for liver damage from taking too much acetaminophen, it’s important to read and follow labels carefully. Practice these tips to keep your child safe:

  • Choose an acetaminophen product made for your child’s age. There can be different products. Never give your child any acetaminophen medicine that is made for an adult.
  • Follow the instructions. The label tells how often to give the medicine. Read it carefully every time to make sure your child is getting the correct dose. Strengths can vary widely between products.
  • Choose the dose for your child’s weight or age. If you know your child’s weight, go by that. If you don’t know how much your child weighs, go by their age.
  • Check labels of other medicines. Before giving your child any other OTC or prescription medicine, make sure it doesn’t also contain acetaminophen. Never give your child more than one medicine with acetaminophen at the same time.
  • Use the measuring device that comes with the medicine. That’s the best way to know you’re giving the right dose.
  • Ask, if you have questions. If you’re not sure how much medicine to give your child or how often, ask your doctor or pharmacist.


If you or your child takes too much acetaminophen, call your doctor or seek medical help right away. The symptoms of acetaminophen overdose include:

  • nausea or vomiting
  • upset stomach
  • loss of appetite
  • sweating

These symptoms may not appear until 12 to 24 hours after taking the medicine.

When taken as directed, acetaminophen is a safe way to control pain and fever. However, it’s important to read all medicine labels and follow directions carefully to make sure you don’t take too much.