How Much Tylenol (Acetaminophen) Can Cause an Overdose?

Liver injury caused by overdoses of Tylenol (acetaminophen) are the leading cause of acute liver failure in the United States, with more than 1,600 cases reported every year. Although doses as low as 2.5-grams per day have been reported to cause liver damage, the U.S. Food and Drug Administration (FDA) recommends a maximum of 3-grams per day due to the risk of overdoses.

What Dose of Tylenol Is Safe?

The maximum amount of Tylenol (acetaminophen) that can be safely ingested is not the same for everyone. Some individuals (especially those who drink alcohol or have liver disease) may be more susceptible to an overdose than other people. Overdoses occur when a person’s liver cannot safely metabolize all of the drug, and produces a toxic metabolite that damages liver cells. Individuals who cannot clear this metabolite from their body or produce more of the metabolite at more likely to develop liver failure (hepatotoxicity). Other factors (nutrition, ethnicity, genetics, etc.) may also play a role in Tylenol overdoses.

Acetaminophen Overdose Amount

If you are taking Tylenol (acetaminophen), talk to your doctor about the dose that is right for you. Most healthy adults can take up to 3 grams of Tylenol per day without suffering liver damage. However, according to this U.S. Food and Drug Administration (FDA) report, rare cases of liver injury have been linked to as little as 2.5 grams of Tylenol per day.

According to this study, published in 2009 in the Journal of Clinical Gastroenterology, “The threshold dose to cause hepatotoxicity is 10 to 15 g of acetaminophen for adults and 150 mg/kg for children.” However, the lowest dose of acetaminophen believed to cause liver injury is about 125-150 mg/kg in adults.

FDA Lowers Limit on Tylenol to Reduce Risk of Overdose

In January 2011, the U.S. Food and Drug Administration (FDA) issued this Safety Communication to announce stronger warnings about the potential for severe liver injury from Tylenol and acetaminophen. They also reduced the maximum amount of acetaminophen to 325-mg per dose. On July 28, 2011, drug-maker McNeill announced new instructions to limit the maximum daily dose from 4,000-mg to 3,000-mg.