Acetaminophen Warnings
Risk of Rare but Serious Skin Reactions
Potentially deadly skin reactions include toxic epidermal necrolysis (TEN), Stevens-Johnson Syndrome (SJS) and acute generalized exanthematous pustulosis (AGEP)
Potential for Severe Liver Injury
Taking more than the recommended dosage of Tylenol or combining the drug with alcohol can result in liver damage

Latest Side Effects Information for Tylenol

As of Mar. 31, 2024, overdoses and drug toxicity were among the most common serious acetaminophen and Tylenol side effects reported to the FDA Adverse Events Reporting System (FAERS) database.

FDA Adverse Events Reporting System (FAERS) Data for Tylenol Side Effects
Total cases reported27,801
Serious cases (including deaths)14,418
Source: FAERS Database
Disclaimer: Information in the FAERS Database dates back to 1968. Submission of reports to the FDA does not inherently indicate that the drug caused an adverse event. Seeking guidance from a healthcare professional before making changes to or stopping any medication is crucial.

“Acetaminophen is a generally safe medication for different types of pain,” Dr. Su Hlaing Hnin, a board-certified internal medicine physician with the Medical Offices of Manhattan, told Drugwatch. “However, if used in excess quantities, it can lead to liver injury or poisoning.”

Common Tylenol Side Effects

Nausea is the most common mild side effect, affecting approximately 34% of users. However, Tylenol, also known as acetaminophen and paracetamol, is generally safe at recommended doses.

“I do not take OTC pain relievers for long term or in high quantities and have not experienced side effects,” Dr. Hnin said. “I have seen patients with side effects from using/overuse of these medications presenting with various symptoms ranging from mild to severe or even fatal medical conditions.”

Common Side Effects of Tylenol (Acetaminophen):
  • Anemia
  • Constipation
  • Diarrhea
  • Dizziness
  • Headache
  • Hypersensitivity reactions
  • Itchiness
  • Nausea
  • Skin rash
  • Sweating
  • Tiredness
  • Vomiting

Vomiting is the second most common side effect after nausea, impacting 15% of studied users. Approximately 5% of people in clinical trials reported vomiting.

In addition, there are more serious side effects to be aware of.

Serious Side Effects of Tylenol
  • Leukopenia (having a low number of white blood cells in circulation)
  • Metabolic and electrolyte imbalances
  • Nausea
  • Nephrotoxicity (a poisonous effect on the kidneys)
  • Neutropenia (low levels of disease-fighting white blood cells, leaving you susceptible to infection)
  • Pancytopenia (deficiency of red and white blood cells and platelets

Liver Damage From Tylenol

Graphic showing how Tylenol overdose leads to liver damage and/or failure.

Published research in the National Library of Medicine shows that acetaminophen is the most common drug-related cause of acute liver failure. Typically, the liver breaks down Tylenol and other acetaminophen products, which are then expelled in urine. However, a byproduct of the drug can be toxic to the liver.

“I have seen patients with side effects from using or overuse of these medications presenting with various symptoms ranging from mild to severe or even fatal medical conditions.”
Dr. Su Hlaing Hnin, Medical Offices of Manhattan

Long-term use of Tylenol can be dangerous.

“Overdosing or long-term use of acetaminophen can be toxic to the liver,” Dr. Taher Saifullah, founder of the Spine and Pain Institute in Los Angeles, told Drugwatch.

The safe daily limit of acetaminophen for healthy adults over 150 pounds is 4,000 mg, but prolonged use at this level can damage the liver, according to Harvard Medical School. It’s best to take the lowest effective dose, which is around 3,000 mg daily.

Regular-strength Tylenol, which is 325 mg, carries a liver damage warning and an overdose warning. For adults, the dosage should not exceed 10 tablets or 3,250 mg in 24 hours. Consult your doctor before taking high doses for chronic pain.

For children under 12, the dosage depends on their weight. Generally, the dose should not exceed five tablets or 1,625 mg in 24 hours. It is inadvisable to give Tylenol or other acetaminophen to a child under six without consulting a doctor.

Taking too much acetaminophen can cause liver damage that is sometimes serious enough to require liver transplantation or cause death. You might accidentally take too much acetaminophen if you do not follow the directions on the prescription or package label carefully or if you take more than one product that contains acetaminophen.

“Prolonged daily use may increase the risk of liver damage,” Trent Carter, FNP-BC, CARN-AP, told Drugwatch. “Continuous use beyond recommended durations can elevate the likelihood of adverse effects.”

Liver damage risk also varies based on sex, age and health status.

Case Study
Woman Experiences Liver Failure After Three Days

Lilowtie Hardine took Tylenol, which contains acetaminophen, for three days to manage pain. Despite following the recommended dosage, she suffered severe side effects, according to court documents.

On January 5, 2011, Hardine experienced symptoms of acute liver failure. She went to Albany Medical Center, where tests showed extremely high liver enzyme levels, which indicated serious liver damage.

Medical Response
Hardine underwent a 72-hour Mucomyst protocol — a process that involves the use of N-acetylcysteine to counteract the effects of acetaminophen. Doctors then recommended her for a liver transplant due to the extent of the damage.

This case highlights the risks of acetaminophen, the active ingredient in Tylenol, which is known to cause liver failure even when taken as directed. Hardine’s experience underscores the importance of being aware of medication side effects and seeking immediate medical attention if adverse reactions occur.

How Acetaminophen Causes Liver Failure

When Tylenol breaks down in your body, it produces a toxic substance called NAPQI that can damage liver cells. If you suspect that you or someone you know has taken too much Tylenol, it’s essential to seek medical help right away to prevent severe liver damage.

When someone takes too much Tylenol or other acetaminophen, it can severely damage their liver. Doctors may pump the stomach, give N-acetylcysteine to block the medication’s absorption or, in severe cases, perform a liver transplant.

“Their liver may never work like before. They will constantly complain about having chronic liver inflammation or scarring — cirrhosis,” Jessica Plonchak, executive clinical director at ChoicePoint Health, told Drugwatch.

Tylenol Overdose Signs and Symptoms

“If you or a loved one is displaying signs like persistent nausea or vomiting, sudden disinterest in food, drowsiness and severe pain in the upper abdomen or stomach then beware, as these signs may indicate an overdose,” Plonchak said.

Acetaminophen overdose symptoms may not appear immediately and can take up to 24 hours, according to the Cleveland Clinic. Keep track of when you took Tylenol or other acetaminophen and the form taken — tablets, capsules or liquid.

4 Distinct Phases of a Tylenol Overdose
Phase I
Occurs in the first 24 hours after ingesting too much acetaminophen. People usually experience nausea, tiredness (fatigue), anorexia, vomiting, paleness (pallor) and excessive sweating (diaphoresis).
Phase II
Phase II: Occurs about 24 to 72 hours after ingestion. Symptoms may include right upper quadrant abdominal pain, nausea and vomiting. People may also experience a fast heartbeat and low blood pressure.
Phase III
Begins about 72 to 96 hours after ingesting Tylenol. Symptoms of liver failure or liver damage include jaundice (yellowing of the skin or eyes), hypoglycemia (low blood sugar), bleeding (coagulopathy) and loss of brain function from toxins. Multiple organ failure and death may also occur at this stage.
Phase IV
Applies to those who survive Phase III. This time in recovery lasts from four days up to three weeks, during which the symptoms resolve.

The Cleveland Clinic reports that about 50,000 ER visits annually are because of acetaminophen overdose or toxicity. Acetaminophen overuse also causes 1,600 cases of acute liver failure and 500 deaths annually in the U.S. According to UCI Health, it’s also the top reason for poison control center calls.

Does Tylenol Present an Autism and ADHD Risk?

While some studies suggest a link between prenatal acetaminophen use and autism/ADHD, researchers have found no conclusive evidence, according to government and medical organizations.

A 2019 study published in JAMA Psychiatry suggests that taking acetaminophen during pregnancy could increase the risk of ADHD and ASD in children. A 2022 study published in the Journal Cureus also found taking acetaminophen during pregnancy may increase the chances of autism and attention/hyperactivity symptoms in children.

However, the American College of Obstetricians, FDA and Gynecologists and Society for Maternal-Fetal Medicine state that the evidence is inconclusive and caution against firm conclusions.

There were 685 FAERS reports mentioning acetaminophen in relation to autism spectrum disorder and 299 FAERS reports of ADHD as of the start of 2024.

Because the jury is still out on whether Tylenol taken during pregnancy creates a risk of autism and ADHD in offspring, pregnant individuals should consult with doctors before limiting necessary acetaminophen use. Avoiding it may have risks.

Lawsuit Information
Lawsuits are being filed by parents of children diagnosed with ADHD or autism allegedly caused by Tylenol use during pregnancy.
Learn More

Rare Allergic Skin Reactions

In rare cases, acetaminophen it can contribute to Stevens-Johnson Syndrome (SJS), acute generalized exanthematous pustulosis and toxic epidermal necrolysis (TEN). Approximately 5.2% of SJS and TEN cases are linked to acetaminophen. The FDA identified the link in 2013 and warned that all three reactions can be fatal.

Rare but Serious Skin Side Effects of Tylenol
Toxic Epidermal Necrolysis
TEN is a life-threatening condition that causes the skin and mucous membrane to peel off extensively, leading to sepsis and death. It was first described in 1956 as a skin eruption resembling scalding.
Acute Generalized Exanthematous Pustulosis
This is a “widespread acute rash characterized by fever and multiple small pustules on a reddish background,” according to the National Cancer Institute.
Stevens-Johnson Syndrome
SJS is similar to toxic epidermal necrolysis. Approximately 80% of SJS cases are caused by medications. SJS causes the skin and sometimes the mucous membranes to peel off and may cause other symptoms throughout the body. Both SJS and TEN involve detached skin, but they are distinguished based on the amount of skin affected.

Genetic variations can heighten an individual’s risk, emphasizing the importance of informed medical decisions and awareness among patients and physicians.

Can Tylenol Cause High Blood Pressure?

Tylenol and other acetaminophen products can cause high blood pressure in some people, according to the National Library of Medicine.

There were 890 FAERS reports of increased blood pressure and 489 reports of decreased blood pressure after taking acetaminophen at the start of 2024.

The regular use of Tylenol and other acetaminophen can increase blood pressure, leading to heart problems and stroke, according to a 2022 study published in the journal Circulation. The study’s authors wrote that it’s essential to be cautious when using acetaminophen, especially if you are at risk for heart disease or stroke.
Talking to your doctor about reducing your dose or finding alternative ways to manage pain can be helpful.

Please seek the advice of a medical professional before making health care decisions.