Follow package directions for prescription and OTC painkillers, and be careful not to combine medications that contain acetaminophen.

An expert panel warns that overdosing on acetaminophen is easier than you think.

RODALE NEWS, EMMAUS, PA—Acetaminophen is one of the most popular over-the-counter painkillers in the U.S., primarily because it doesn’t irritate stomachs the way that aspirin and ibuprofen can. It’s used in a variety of medications, from Tylenol to Dayquil Sinus, but overdosing on it can lead to serious liver damage. At a meeting that took place earlier this week, a U.S. Food and Drug Administration advisory panel found that the risks of acetaminophen-related liver damage are so serious, and the public so unaware of them, that major steps need to be taken. Some say they’re overdue. “Thirty-two years ago, the FDA recommended that there be strong warnings on acetaminophen products, and those recommendations were finally put in place three months ago,” says Sidney M. Wolfe, MD, director of the Health Research Group of Public Citizen and the consumer representative on the advisory panel. “Huge numbers of people have died from acetaminophen liver toxicity, and they wouldn’t have if the FDA had moved on its recommendations.”

THE DETAILS: Too much acetaminophen can cause the liver to produce a toxic metabolite that binds to liver proteins and damages cells, and you may be overdosing on the drug without realizing it, says the FDA. Cases of acetaminophen overdose often result from a person taking more pills a day than she should, or by combining products that contain acetaminophen without realizing it, usually a prescription product containing acetaminophen plus an over-the-counter drug like Tylenol. According to a 2005 study published in the journal Hepatology, acetaminophen-related liver injuries were the leading causes of acute liver failure from 1998 to 2003, and among patients in the study, nearly half overdosed on the drug without realizing it.

At this recent meeting, the advisory panel proposed lowering the current recommended maximum dosage, 4 grams, because exceeding that even by a small amount can lead to liver damage. They also recommended lowering the maximum levels of acetaminophen found in over-the-counter pills from 500 milligrams to 325 mg.

For prescription products containing acetaminophen, the panel recommended improving labeling. Currently, acetaminophen is listed as on many prescriptions as “APAP.” The panel also proposed a ban on Vicodin and Perkoset, two powerful painkillers that combine narcotic ingredients with acetaminophen. The problem with these, says Dr. Wolfe, is that people become tolerant to the amounts of narcotics in those pills, and doctors have to up the dose of narcotics to keep them from working. “But it’s a fixed combination, so if you increase the dose of a narcotic, you also increase the dose of acetaminophen.”