Tylenol Side Effects

The Tylenol brand carries 30 products using the same active ingredient called acetaminophen.

As of the latest data published on Dec. 31, 2023, drug toxicity — having too much acetaminophen in a person’s system — and overdoses were two of the common serious acetaminophen and Tylenol side effects reported to the FDA Adverse Events Reporting System (FAERS) database.

Tylenol toxicity can lead to serious liver damage.

Regular-strength Tylenol carries a liver warning and an overdose warning. The daily dosage is limited to no more than 10 tablets in 24 hours for adults and five tablets for children under 12. Do not give Tylenol or other acetaminophen to a child under six without consulting a doctor.

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

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

Published research shows acetaminophen is the most common drug-related cause of acute liver failure. Typically, Tylenol and other acetaminophen products are broken down by the liver and eliminated in urine. However, a byproduct of the drug can be toxic to the liver.

As of the beginning of 2024, the FAERS database had received 3,445 reports of acute liver failure, 2,190 reports of liver injury and 1,190 reports of liver disorder related to Tylenol and other acetaminophen products.

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, not exceeding 3,000 mg daily. Consult your doctor before taking high doses for chronic pain.

“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.

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.

Serious cases of acetaminophen overdose can result in acute liver failure.

“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.

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.

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. However, the jury is still out on whether Tylenol taken during pregnancy creates a risk of autism and ADHD in offspring.

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.

While studies suggest a link between prenatal acetaminophen use and autism/ADHD, researchers have found no conclusive evidence, according to government and medical organizations. The FDA, American College of Obstetricians and Gynecologists and Society for Maternal-Fetal Medicine state that the evidence is inconclusive and caution against firm conclusions.

Pregnant individuals should consult with doctors before limiting necessary acetaminophen use, as avoiding it may have risks.

Acetaminophen is generally safe. Still, in rare cases, it contributes to Stevens-Johnson Syndrome, acute generalized exanthematous pustulosis and toxic epidermal necrolysis. 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.

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

Tylenol and other acetaminophen products are known to cause 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.