Small Overdoses of Acetaminophen Over Time Can Be Deadly

Even small overdoses of acetaminophen, when taken over time, can be fatal, a new study has revealed. Acetaminophen, especially in the form of Tylenol, has been a constant presence in many U.S. homes for over 50 years.

Because of their familiarity with it, many consumers aren’t aware that Tylenol and other forms of acetaminophen carry a risk of significant health affects. For example, acetaminophen can cause serious liver damage if too much is taken. Most recently, we wrote about links between acetaminophen and asthma.

The new study found that taking even a little too much Tylenol over a few days can lead to fatal overdosing or so-called “staggered overdoses,” said MSNBC, explaining that these overdoses occur when the daily recommended dose is repeatedly exceeded in small amounts. This type of overdose differs from a single overdose in which a person takes too many pills at one time.

The study, which appears online in the British Journal of Clinical Pharmacology, found that staggered acetaminophen overdoses were deadlier than single overdoses, even though smaller amounts of the medication are taken in overdoses that are spread over time, noted MSNBC. Staggered overdoses might not be readily obvious to physicians, noted the researchers and those suffering from staggered overdosing may test with blood levels of the drug in amounts smaller than what would point to an overdose, even if their liver is significantly damaged, said MSNBC.

Kenneth Simpson, a researcher with Scotland’s University of Edinburgh advises people who take acetaminophen to stay well within the recommended limits and to take even less when taking other painkillers, wrote MSNBC. An overdose, said the team, is when more than 4,000 milligrams of acetaminophen is taken in a 24-hour time frame; this is the same maximum dose as set forth by the U.S. Food and Drug Administration (FDA), said MSNBC. Also, said Simpson, physicians should be aware that criteria that identifies a traditional overdose does not work well for identifying staggered overdoses.

As we’ve mentioned, the current recommended maximum daily dose on labels of acetaminophen is 4,000 mg (what is found in eight typical extra-strength pills). Many acetaminophen injuries occur because a person is taking two acetaminophen products at one time, and this can exceed the recommended daily limit. Many patients may not know that the prescription painkiller they’re taking contains acetaminophen and often they aren’t warned to avoid other acetaminophen-containing products.

The team reviewed data from 663 patients admitted to an Edinburgh hospital between 1992 and 2008 and who were diagnosed with liver problems caused by acetaminophen, also known as paracetamol, said MSNBC. About one-quarter of the patients—161—had taken staggered overdoses. For the most part, the patients took 24 grams—24,000 milligrams—of acetaminophen over several days, while single overdoses involved consumption of 27 grams—27,000 milligrams—which is six times the recommended dose for one day.

Of the patients studied, 60 died—37.3% mortality rate—from a staggered overdose, and 140 from a single overdose (27.8% mortality rate); staggered overdose patients were likelier to also suffer liver and brain problems, to need kidney dialysis, and to require breathing assistance, said MSNBC. In the staggered overdose group, nearly 60% said they took the medication for pain relief, such as for abdominal, muscle, headache, or tooth pain. Simpson explained that in a staggered overdose, acetaminophen most likely accumulates in the liver, killing the cells

According to an article published in the Los Angeles Times earlier this year, acetaminophen single overdoses resulted in more than 40,000 calls to poison control centers in 2009; such overdoses are among leading causes of acute liver failure.