Acetaminophen - 10 Things You Should Know

Safe Use Decreases Unwanted Side Effects

Tylenol Extra Strength is sold over-the-counter at a drugstore June 30, 2009 in Chicago, Illinois.
Scott Olson/Getty ImagesNews/Getty Images

Acetaminophen (brand names Tylenol, Triaminic, and others) is a widely used drug which is considered safe when used appropriately. Safe use decreases the chance for undesirable side effects. Here are 10 things you should know:

1 - Acetaminophen is a medication prescribed for pain relief and fever reduction.

Acetaminophen is classified as an analgesic and antipyretic. It is the most commonly prescribed and widely-used pain relievers and fever reducers in the world.

Acetaminophen does not have anti-inflammatory properties though. Acetaminophen is used to manage many health problems, including arthritis pain.

2 - Acetaminophen is contained in more than 100 different products and combination products.

Acetaminophen is contained in countless pain formulations, cold products, sinus preparations, and more (e.g., Sinutab, Midol, Ultracet, Dristan). The wide availability of acetaminophen, sold over-the-counter and in prescription products, make 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, serious side effects and potentially fatal consequences may occur.

3 - 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 (acetaminophen) is 325 mg per pill. Extra strength Tylenol (acetaminophen) is 500 mg per pill. For adults, 8 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 U.S. 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.

4 - You must be aware of the cumulative effect when taking various products which contain acetaminophen.

As previously explained, many products contain acetaminophen. It is your responsibility to add up the amount of acetaminophen that you are ingesting daily. Even if taking acetaminophen from more than one product, add the total amount to be sure you are not exceeding the daily allowable dose. For example, if you take two Lortab 10-500 per day, that is equal to 1000 mg acetaminophen since one Lortab contains 500 mg acetaminophen. Lortab contains hydrocodone and acetaminophen.

If in addition to Lortab for pain, you also take cold or sinus medication which contains acetaminophen, you must add the total amount ingested (e.g., add up the acetaminophen in both Lortab and the cold medication) in order to be aware of the cumulative effect. The label on Tylenol recommends that you not take more than one product at a time which contains acetaminophen to ensure that you won't exceed maximum allowable dosages.

5 - 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 should take acetaminophen. The combination of alcohol and acetaminophen can be seriously damaging to the liver, with possible fatal outcomes.

6 - 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 were added to the label of acetaminophen. Even if you have taken acetaminophen without a problem, serious skin reactions can occur at any time.

7 - Symptoms associated with acetaminophen overdose can be serious and require immediate medical attention.

The symptoms can occur whether the overdose is accidental or not:

  • 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

8 - There are recommendations and guidelines for how long you should take acetaminophen if you are self-treating.

Recommendations suggest that you may take acetaminophen for up to 3 days when treating a fever, and for up to 10 days when treating pain. If symptoms persist beyond that time frame, consult with a doctor to see if you should continue with acetaminophen or change your treatment plan.

9 - Acetaminophen is classified as FDA Pregnancy Category B, meaning, it is unlikely the drug would harm an unborn baby.

If you are pregnant, do not take acetaminophen without discussing it with your doctor. Acetaminophen passes into breast milk. Though it is considered safe to use during breastfeeding, discuss it with your doctor.

10 - When used as directed, acetaminophen is considered generally safe. That's the bottom line.

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
  • Concomitant use of acetaminophen with alcohol (i.e., taken together) or with other drugs that can also potentially cause liver damage

UPDATE March 2016: Study results published in the Lancet suggest that acetaminophen is no more effective than placebo (a sugar pill) for treating hip or knee pain from osteoarthritis.

Sources:

Acetaminophen. Drugs.com. Revised 01/11/2016.
http://www.drugs.com/acetaminophen.html

Drug Information: Acetaminophen. MedlinePlus. Revised 08/15/2014.
https://www.nlm.nih.gov/medlineplus/druginfo/meds/a681004.html

FDA Warns of Rare Acetaminophen Risk. FDA. 08/01/2013.
http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm363010.htm

Effectiveness of non-steroidal anti-inflammatory drugs for the treatment of pain in knee and hip osteoarthritis: a network meta-analysis. Da Costa et al. The Lancet. Published online 03/17/2016.
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2816%2930002-2/abstract

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