Overview and Information About Acetaminophen

Bottle of acetaminophen
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Acetaminophen, the drug in the brand name medicine Tylenol, is an analgesic (painkiller) used to treat minor aches and pains as well as to reduce fever. It's found in many drugs other then Tylenol, including Ofirmev, FeverAll, and a host of others. Sometimes it's the only ingredient, but often it's added to another drug or multiple drugs.

Acetaminophen is found in both over-the-counter (OTC) and prescription medications and most households probably have it in their medicine cabinet at some point.

Acetaminophen is considered safe when used correctly. It is imperative that you take it exactly as directed to avoid undesirable and potentially deadly side effects.


Acetaminophen is classified as an analgesic and antipyretic (fever reducer). It's the most widely used pain reliever and fever reducer in the world. It does not have anti-inflammatory properties but is often used to manage pain from health problems that do involve inflammation, including arthritis pain.


Acetaminophen is contained in more than 100 different products and combination products, including:

  • Pain formulations
  • Cold products
  • Sinus preparations

The wide availability of acetaminophen, sold over-the-counter and in prescription products, makes it one of the most common drugs associated with intentional or accidental poisoning.

If you take multiple products that contain acetaminophen and exceed the maximum allowable daily dose, you could face serious side effects and potentially fatal consequences.

Dosage Information

The maximum allowable daily dose of acetaminophen is 4 grams (or 4000 mg) in adults and 90 mg/kg in children.

Acetaminophen is available as a tablet, chewable tablet, capsule, caplet, geltab, gelcap, extended-release tablet, or liquid suspension to be taken by mouth, with or without food. It is also available as a suppository.

Regular strength Tylenol contains 325 mg of acetaminophen per pill. Extra strength Tylenol contains 500 mg of acetaminophen per pill. For adults, eight extra-strength acetaminophen tablets is the maximum allowed per day. If you exceed that amount, you risk serious consequences.

In 2011, the FDA proposed changes to the maximum dosage for acetaminophen. On August 30, 2013, Johnson & Johnson announced that a warning would appear on the cap of bottles of Extra Strength Tylenol sold in the US starting in October of that year and on other Tylenol bottles in the months that followed. The warning was to inform the buyer that over-the-counter drugs containing acetaminophen can cause sudden liver failure when too much is taken.

Cumulative Effect

You must be aware of the cumulative effect when taking various products which contain acetaminophen. Keep track of the amount of this drug you're getting from every source, if you're taking more than one, to be sure you are not exceeding the daily allowable dose.

For example, the drug Norco contains hydrocodone and acetaminophen. If you take two Norco 10-325 per day, that is equal to 650 mg acetaminophen since one Norco contains 325 mg acetaminophen. If, in addition to Norco for pain, you also take cold or sinus medication which contains acetaminophen, you must add the amount in that to the amount you're getting from Norco.

The label on Tylenol recommends that you not take more than one product at a time that contains acetaminophen to ensure that you won't exceed maximum allowable dosages.

Acetaminophen and Alcohol

Drinking alcoholic beverages while taking acetaminophen is not advised. If you drink three or more alcoholic beverages every day or have had alcoholic liver disease, ask your doctor if you can take acetaminophen. The combination of alcohol and acetaminophen can be seriously damaging to the liver, with possible fatal outcomes.

Possible Side Effects

Acetaminophen side effects can be serious. Know when you should call your doctor instead of assuming the problem will disappear. Certain side effects may be signs of an allergic reaction or a situation that requires immediate medical attention, such as:

  • Rash
  • Hives
  • Itching
  • Swelling
  • Hoarseness
  • Difficulty breathing
  • Difficulty swallowing

In 2013, the FDA warned about rare serious skin reactions that can occur with acetaminophen. According to the FDA:

"Stevens-Johnson Syndrome and toxic epidermal necrolysis are the two most serious skin reactions linked in rare cases to acetaminophen. They usually require hospitalization and can cause death."

A third skin reaction, acute generalized exanthematous pustulosis, usually resolves within two weeks of stopping the medication. Warnings about these skin reactions are on the acetaminophen label.

Even if you've previously taken acetaminophen without a problem, serious skin reactions can occur at any time.

Know Overdose Symptoms

Symptoms associated with acetaminophen overdose can be serious and require immediate medical attention. The symptoms associated with overdose can occur whether it is accidental or not and include:

  • Nausea
  • Vomiting
  • Loss of appetite
  • Confusion
  • Sweating
  • Extreme fatigue
  • Unusual bleeding or bruising
  • Pain in stomach (especially upper right portion)
  • Yellowish skin or eyes
  • Flu-like symptoms
  • Diarrhea
  • Irregular heartbeat

If you or someone else starts exhibiting these symptoms, get medical help right away.

How Long to Take Acetaminophen

If a doctor prescribes or recommends an acetaminophen product, ask how long you should stay on the medication.

If you're self-treating, the recommendations suggest taking acetaminophen for:

  • Up to 3 days for fever
  • Up to 10 days for pain

If symptoms persist beyond that time frame, talk to a doctor to see if you should continue with acetaminophen or change your treatment plan.

Use During Pregnancy

Acetaminophen is classified as FDA Pregnancy Category B, meaning, it is unlikely the drug would harm an unborn baby. Even so, if you are pregnant, discuss it with your doctor before taking this (or any) drug.

Acetaminophen does pass into breast milk. Though it is considered safe to use during breastfeeding, this also should be discussed with your doctor.

A Word From Verywell

When taken according to directions, side effects from acetaminophen are rare. The most serious side effect is liver damage. Kidney toxicity is also a possibility. The risk of liver damage increases with:

  • Large doses of acetaminophen
  • Chronic use of acetaminophen
  • Taking acetaminophen with alcohol or with other drugs that may also cause liver damage

The fact that acetaminophen is sold as an OTC pain reliever doesn't mean it is without possible side effects, including some that are potentially severe. As with any medication, the benefits and risks should be weighed.

If you take acetaminophen for any reason, pay attention to the directions and safety warnings.

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