Tylenol is one of the most commonly used drugs in the United States. The active ingredient in Tylenol is a drug called acetaminophen. Acetaminophen-containing products such as Tylenol are used by over 50 million Americans weekly to treat conditions such as pain, fever, and the aches and pains associated with the common cold and flu. If taken at recommended doses, Tylenol (acetaminophen) causes very few side effects; however, taking more than the recommended dose can cause severe liver damage, acute liver failure, and even death. Overdoses can result when patients accidentally take more than the recommended dose of Tylenol (or another acetaminophen product) or take over one acetaminophen-containing product simultaneously.
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Numerous studies have demonstrated that acetaminophen overdose is a leading cause of liver damage and liver failure in the United States. The FDA notes that “the extent of liver failure cases reported in the medical literature provides an important signal of concern.” The Agency also concedes that ingesting even a small amount of Tylenol (acetaminophen) over the recommended total daily dose may lead to liver injury. It even acknowledges that “currently recommended doses and tablet strengths of acetaminophen leave little room for error…”.
In addition to Tylenol, acetaminophen is an active ingredient in over 600 over-the-counter and prescription medications. As such, individuals may inadvertently use over one acetaminophen-containing product at the same time. For example, acetaminophen is a common ingredient in many multiple-ingredient medications, such as Sudafed Triple Action™ and NyQuil. Someone who takes Tylenol for a headache and subsequently takes one of these combination medications to treat the aches and pains associated with the flu may unknowingly consume more than the recommended daily dose of acetaminophen.
Further complicating the picture for consumers is that acetaminophen may be challenging to identify as an ingredient. Some prescription medications that contain acetaminophen label the ingredient simply as “APAP.” The lack of clear labeling may also lead consumers to accidentally ingest more than one product that contains acetaminophen.
Maximum Daily Dosage
In 2009, an FDA advisory panel recommended dropping the maximum daily dose below the established level of 4,000 mg and also asked the FDA to reduce the single adult dose to 675mg. The FDA chose not to follow the advisory panel’s recommendations.
However, in January 2011, the FDA announced a mandate to all manufacturers of prescription acetaminophen combination products (such as Tylenol with Codeine #3) to limit the maximum amount of the ingredient in these products to 325 mg per dosage unit (tablet, capsule, drops, syrups, etc.). The agency required manufacturers of prescription products containing acetaminophen to include a boxed warning on their labels about the risk of liver injury. The FDA also asked manufacturers of over-the-counter products to reduce the maximum daily dose of acetaminophen from 4 grams to 3 grams (or 3,000 milligrams) per day.
In July 2011, the manufacturer of Tylenol, J&J’s McNeil Consumer Healthcare, announced that it was voluntarily lowering the maximum daily dose instructions for Extra Strength Tylenol (an over-the-counter best-seller) to six pills a day (3,000 mg) to reduce the risk of acetaminophen overdose. McNeil also announced plans to lower the maximum daily dose for Regular Strength Tylenol and its other acetaminophen-containing products starting in 2012.
Important Tylenol Facts You Should Know
Signs and Symptoms of Tylenol Liver Damage:
The symptoms associated with Tylenol-induced liver injury can take several days to appear, even in severe cases. They may also be non-specific and mimic flu symptoms, making them even harder to identify.
Know your risk: An individual’s susceptibility to livery injury from Tylenol (acetaminophen) varies. People who have increased sensitivity may experience toxic effects at lower doses, as may those who use alcohol or who have pre-existing liver disease. Talk to your doctor if you drink over three alcoholic drinks daily, take the prescription blood thinner warfarin, or have liver disease. Even if you take Tylenol (acetaminophen) at the recommended dose, you may still be at an increased risk for liver disease.
Infants and children: Products designed specifically for children (such as Children’s Tylenol and Infants’ Tylenol) contain acetaminophen in different strengths. Liquid formulations designed for infants and toddlers are usually more potent (more concentrated). Those designed for older children are generally less concentrated. Failure to distinguish between the two strengths can cause accidental overdose for younger children and infants.
Advertising tactics: Advertisements for over-the-counter acetaminophen-containing products such as Tylenol frequently emphasize their effectiveness. Unlike prescription medications, these advertisements are not required to offset these messages of warning information about the associated risks. Since the association between acetaminophen and liver damage is not well-known among consumers, consumers may not be fully aware of the potential risks.
Read labels carefully: All medications list their ingredients on their label. For over-the-counter medications such as Tylenol, refer to the “Drug Facts” label under the section titled “Active Ingredients.” If your medicine contains acetaminophen, you will find it listed there. Prescription medications will contain the ingredient labeled as “acetaminophen” or “APAP.”
Tylenol Liver Injury Medical Literature
- Blieden M, et al. A perspective on the epidemiology of acetaminophen exposure and toxicity in the United States. Expert Rev Clin Pharmacol. 2014 May;7(3):341-348. doi: 10.1586/17512433.2014.910343. Epub 2014 Apr 3. PMID: 24694035.
This study comprehensively reviews the epidemiology of acetaminophen exposure and toxicity in the United States. The authors examined data from multiple sources, including hospital records and poison control centers, to provide a detailed analysis of the incidence, severity, and outcomes of acetaminophen toxicity.
This is hardly an anti-acetaminophen study. The authors believe the drug is generally safe when used as directed. However, the study also found significant risks associated with the misuse or overdose of acetaminophen, including liver damage and even death.
The study identified several factors contributing to the risk of acetaminophen toxicity, including unintentional overdoses due to multiple medications containing acetaminophen, intentional overdoses in suicide attempts, and inadvertent overdoses due to errors in medication administration.
- Watkins P, et al. Aminotransferase elevations in healthy adults receiving 4 grams of acetaminophen daily: a randomized controlled trial. JAMA. 2006 Apr 5;296(13):87-93. doi: 10.1001/jama.296.13.87. PMID: 16820551.
This study aimed to determine the effects of therapeutic doses of acetaminophen on liver function tests in healthy adults. The study enrolled 145 healthy adults who were randomly assigned to receive either 4 grams of acetaminophen per day or a placebo for 14 days. The study measured levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), which are enzymes that are released when liver cells are damaged. The study also measured bilirubin, which is a waste product that is produced when the liver breaks down red blood cells.
The study found that participants who received acetaminophen had higher levels of ALT and AST compared to those who received the placebo. The study also found that a small number of participants who received acetaminophen had elevated bilirubin levels, which can be a sign of liver damage. However, the study did not find clinically significant liver damage or liver failure cases that would give cause for alarm. The take-home message here appears to be that acetaminophen is not good for your liver but it is unlikely to be a proven cause of a liver injury.