Tylenol (Acetaminophen)

Tylenol is a well-known pain reliever and fever reducer. Produced by Kenvue, a spin-off of Johnson & Johnson, Tylenol is the brand name for a medication called acetaminophen, also known as paracetamol.

You can buy Tylenol without a prescription, and it’s often found in over-the-counter products like cold medicines. The drug is also available in some prescription medications, such as the painkillers Percocet and Vicodin.

While Tylenol’s pain and fever-reducing mechanisms are not fully understood, experts speculate that the drug blocks the production of cyclooxygenase enzymes. These enzymes can cause inflammation, pain and fever. Blocking their production may prevent the transmission of pain signals and lower your body temperature.

Unlike pain relievers that contain ibuprofen, including Advil and Motrin, Tylenol doesn’t help with inflammation.

Tylenol is generally safe when taken at recommended doses. Nausea is the most common mild side effect, affecting up to 34% of users.

Vomiting is the second most common side effect, impacting 15% of users. Fortunately, most people tolerate Tylenol well.

Tylenol’s label carries warnings about possible liver damage and allergic or skin reactions. You should be careful not to take more than 4,000 milligrams within 24 hours.

As of November 19, 2025, the U.S. Food and Drug Administration’s (FDA) Adverse Events Reporting System (FAERS) had received 34,866 reports of adverse events associated with Tylenol. This included cases 16,616 that were categorized as serious and 2,089 deaths.

You should stop taking Tylenol and seek immediate medical attention if you experience severe side effects.

Tylenol and High Blood Pressure

According to a 2022 study, using Tylenol and other acetaminophen products can increase blood pressure in people who already have high blood pressure (known as hypertension). Researchers wrote that it’s essential to be cautious when using acetaminophen, especially if you are at risk for heart disease or stroke.

A separate study also conducted in 2022 had similar results. Researchers in that study found “a significant correlation between the use of acetaminophen and elevated systolic blood pressure.”

Talking to your doctor about reducing your acetaminophen dose or finding alternative ways to manage pain and fever can be helpful, especially if you have hypertension.

Acetaminophen Overdose and Liver Failure

The FDA reported that high doses of acetaminophen can lead to liver failure, potentially requiring a transplant and posing life-threatening risks.

Acetaminophen overdose ranks as the second leading reason for liver transplants around the world. In the U.S, it is the top cause of liver failure. Each year, acetaminophen poisoning leads to approximately 56,000 visits to emergency rooms, 2,600 hospitalizations and 500 deaths.

About half of these poisonings happen accidentally, often because people misunderstand the dosing instructions or use multiple acetaminophen-containing products at once.

“Liver damage from acetaminophen is particularly dangerous because it often develops silently until it reaches a critical stage,” Dr. John Abroon, a board-certified internist and primary care physician, told Drugwatch.

He said this means patients will often show up at emergency rooms with severe liver damage.

“Despite being preventable with proper use, acetaminophen overdose remains a leading cause of acute liver failure due to factors like lack of public awareness, misuse and the drug’s widespread availability,” Dr. Abroon said.

You might exceed the safe limit for acetaminophen if you don’t follow the label instructions or if you use more than one product that contains it. Be cautious not to exceed 4,000 milligrams per day.

If you are experiencing complications like difficulty breathing, skin issues or confusion after taking Tylenol, contact your doctor immediately.

Acetaminophen overdose symptoms may not appear immediately and can take up to 24 hours to start. Keep track of when you took Tylenol or other acetaminophen and whether you took tablets, capsules or liquid.

It’s reported that acetaminophen overdose is the number one reason people in the U.S. contact poison control centers.

Studies have suggested an association between Tylenol use during pregnancy and a higher risk for autism and ADHD (attention-deficit/hyperactivity disorder) in children.

A 2019 study found that higher levels of acetaminophen in newborns’ umbilical cord blood were linked to a greater risk of ADHD and autism spectrum disorder (ASD) in childhood. The risk increased with higher exposure levels, suggesting a possible dose-response relationship.

Another study published in 2022 found that children whose mothers used acetaminophen while pregnant were more likely to have attention and sleep problems at age three. These links remained even after accounting for stress during pregnancy.

In September 2025, the FDA sent a letter to doctors warning of a potential connection between Tylenol use during pregnancy and the development of autism and ADHD.

The letter noted that some studies “have described that the risk may be most pronounced when acetaminophen is taken chronically throughout pregnancy to childbirth.” It cautioned doctors to consider minimizing the use of Tylenol during pregnancy for low-grade fevers.

A label update to Tylenol was also initiated. It included information on a potential autism and ADHD connection. However, the FDA noted that no causal relationship has been established between Tylenol and autism.

Tylenol ADHD & Autism Lawsuits

In 2022, a federal panel consolidated Tylenol lawsuits from around the United States into a multidistrict litigation (MDL) in the United States District Court for the Southern District of New York. MDLs allow similar lawsuits to be grouped into a single litigation to expedite the legal process.

The lawsuits claimed mothers who took over-the-counter acetaminophen during pregnancy may have an increased risk of their children developing ASD or ADHD.

Over 700 lawsuits were filed in the MDL, and 58 cases are still active as of November 3, 2025. The litigation targets large retail pharmacies, including CVS, Walgreens and Walmart.

If you believe you or your child experienced severe side effects or injury from acetaminophen, it’s critical to get immediate medical help.

If you’re thinking about filing a Tylenol lawsuit due to problems you or your children developed after taking the drug, you can get a free case evaluation from Drugwatch. Just complete a brief form, and a member of our team will contact you to determine if you have a case.