Unintended acetaminophen overdoses rising

The drug is viewed as safe when taken at the right dosage, yet many experts are concerned that inadvertent overuse may be too easy.

By Victoria Stagg Elliott, AMNews staff. Dec. 26, 2005.

Penny Tenzer, MD, a family physician in Miami, occasionally sees a patient with elevated liver enzymes linked to taking too much acetaminophen. But unlike the majority of people who overdose on this drug, these patients were not deliberately trying to harm themselves. Rather, they took various over-the-counter medications without realizing that they all contained this ingredient.

"People are frequently so unaware of the many things that have acetaminophen in them and that there is a maximum daily dose," said Dr. Tenzer, who is the vice chair of the Dept. of Family Medicine at the University of Miami School of Medicine.

The fact that acetaminophen taken at higher than recommended doses can harm the liver is not new, and the possibility that this drug could be used to attempt suicide has long been acknowledged. Drug safety experts are increasingly recognizing, however, that not all overdoses are deliberate, and that this is a serious public health issue.

"We need to take a fresh look at patients who may be overusing acetaminophen," said Robert Gillette, MD, a retired family physician in Poland, Ohio, and one of the contributing authors of the American Academy of Family Physicians 2002 monograph, "Appropriate Use of Common OTC Analgesics and Cough and Cold Medications."

More recently, a Food and Drug Administration analysis of several national databases published online in Pharmacoepidemiology and Drug Safety last month found that the rate of overdoses classified as inadvertent ranged from 8% to 26%, depending on the dataset used. A study published in Hepatology prospectively followed several hundred patients with acute liver failure over six years. For those whose conditions were associated with high amounts of acetaminophen, 48% of the doses were inadvertent.