Edited By : Amy Edel
This page features 13 Cited Research Articles
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Common Side Effects of Tylenol

Most patients tolerate acetaminophen well and don’t experience many or serious Tylenol side effects when they take it as directed. Gastrointestinal issues or stomach upset, particularly nausea, are the most common side effects.

Common side effects of Tylenol include:
  • Abdominal Pain
  • Constipation
  • Diarrhea
  • Dizziness
  • Headache
  • Indigestion
  • Injection site pain (with IV product)
  • Itchiness
  • Nausea
  • Sweating
  • Tiredness
  • Vomiting

Tylenol is the most well known brand containing the pain reliever acetaminophen, which is known as paracetamol in Europe, Australia, New Zealand and India. Many products, including cough and cold remedies, contain acetaminophen.

Serious Side Effects of Tylenol

Acetaminophen is a common ingredient in more than 100 over-the-counter medications, such as those for colds and flu. Acetaminophen poisoning may occur if people take too many products containing acetaminophen at the same time.

Acetaminophen is also associated with a risk of rare but severe skin reactions, which can be fatal in extreme cases. These reactions are Stevens-Johnson Syndrome, toxic epidermal necrolysis and acute generalized exanthematous pustulosis. If you develop a skin reaction, stop taking Tylenol immediately and see your doctor.

One study found that regular intake of 4 grams of acetaminophen can increase blood pressure in people with hypertension approximately 4%. This can then increase the risk of a cardiovascular event.

Is There a Link Between Tylenol and Autism?

Experts don’t know the specific causes of autism spectrum disorder. Because acetaminophen is the most common drug taken during pregnancy, researchers are actively working to answer the question – “Does Tylenol cause autism?”

Current research suggests that taking Tylenol during pregnancy may impact neurodevelopment. One meta-analysis concluded that acetaminophen taken during pregnancy was 19% more likely to be associated with ASD symptoms in children.

Families of children who developed ASD are filing Tylenol autism lawsuits against retailers, manufacturer Johnson and Johnson and generic acetaminophen makers. Lawsuits seek compensation and to hold defendants accountable for alleged failure to warn consumers that using Tylenol during pregnancy could lead to autism.

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Was your child diagnosed with ADHD or autism after you used Tylenol during pregnancy?
Get your free case review today.

Does Tylenol Cause Liver Damage?

Taking more Tylenol than recommended can cause liver injury. Taking appropriate doses for an extended time can also put you at higher risk for liver damage.

The U.S. Food and Drug Administration required manufacturers to limit the amount of acetaminophen in each tablet or capsule to no more than 325 milligrams. The agency was concerned about the potential for liver failure when people take multiple products containing acetaminophen and exceed the maximum dose of 4000 mg in a 24-hours.

Alcohol when combined with acetaminophen substantially increases the risk of acute liver failure. Patients with liver disease should speak to their doctor about the appropriate dosage of acetaminophen.

Tylenol Overdose

Acetaminophen toxicity is the most common cause of liver transplantation in the U.S. An estimated 50% of Tylenol overdoses are accidental. Many consumers aren’t aware of how many different products they take may contain acetaminophen and sometimes take them at the same time.

Initial signs of Tylenol overdose include abdominal pain, nausea and vomiting. There are four stages to a Tylenol overdose.

  • Phase 1:Between 12 and 24 hours after a toxic dose people typically experience nausea, vomiting, lethargy, weakness and excessive sweating (preclinical toxic effects).
  • Phase 2: At 24 - 48 hours after a toxic dose, there may be right-side tenderness or pain, jaundice and test results showing liver impairment (hepatic injury). Doctors usually administer an antidote – acetylcysteine.
  • Phase 3: Three days after a toxic dose the liver fails (hepatic failure). Nausea, vomiting, confusion and coma, as well as kidney failure and death can occur.
  • Phase 4: This is a recovery phase. Approximately 70% of those who enter phase four recover entirely.

Early signs of liver toxicity can initially be subtle. Recognizing the signs can mean earlier treatment. Being given N-acetylcysteine within eight hours of a Tylenol overdose can protect against liver toxicity.

Whether taking Tylenol yourself or giving it to your children, following dosing instructions and making sure you’re not taking multiple medications that contain acetaminophen at the same time is critical. Read instructions and ingredients carefully.

Please seek the advice of a qualified professional before making decisions about your health or finances.
Last Modified: May 3, 2023

13 Cited Research Articles

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  1. Agrawal, S. & Khazaeni, B. (2023, February 12). Acetaminophen Toxicity. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK441917/
  2. O’Malley, G. & O’Malley, R. (2022, September). Aspirin Poisoning. Retrieved from https://www.merckmanuals.com/home/injuries-and-poisoning/poisoning/aspirin-poisoning
  3. Yaqoob-Khan, F. et al. (2022, July 18). A Systematic Review of the Link Between Autism Spectrum Disorder and Acetaminophen: A Mystery to Resolve. Retrieved from https://www.cureus.com/articles/84979-a-systematic-review-of-the-link-between-autism-spectrum-disorder-and-acetaminophen-a-mystery-to-resolve#!/
  4. U.S. Food & Drug Administration. (2022, June 9). Acetaminophen. Retrieved from https://www.fda.gov/drugs/information-drug-class/acetaminophen
  5. National Library of Medicine. (2022, March 21). Acetaminophen. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK501194/
  6. I.M. MacIntyre et al. (2022, February 7). Regular Acetaminophen Use and Blood Pressure in People With Hypertension: The PATH-BP Trial. Retrieved from https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.121.056015
  7. Cendejas-Hernandez, J. (2022, February 17). Paracetamol (acetaminophen) use in infants and children was never shown to be safe for neurodevelopment: a systematic review with citation tracking. Retrieved from https://link.springer.com/article/10.1007/s00431-022-04407-w
  8. Kwok, J. et al. (2022). Analgesic drug use in pregnancy and neurodevelopment outcomes: an umbrella review. Retrieved from https://www.sciencedirect.com/science/article/pii/S0149763422000963?via%3Dihub
  9. National Institute of Diabetes and Digestive and Kidney Diseases. (2016, January 28). LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, Acetaminophen. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK548162/
  10. UC San Diego Health. (n.d.). Drug-Induced Liver Injury. Retrieved from https://health.ucsd.edu/care/liver-disease/drug-induced-liver-injury/
  11. Johnson-Arbor, K. (n.d.). Acetaminophen: Take It Safely. Retrieved from https://www.poison.org/articles/acetaminophen-take-it-safely
  12. The University of Chicago. (n.d.) Acetaminophen Poisoning. Retrieved from https://pedclerk.bsd.uchicago.edu/page/acetaminophen-poisoning
  13. McGill University Department of Critical Care. (n.d.) Acetaminophen. Retrieved from https://www.mcgill.ca/criticalcare/education/teaching/teaching-files/toxicology-series/acetaminophen