Moderate overdoses of painkillers such as Tylenol can cause severe liver damage in people who are too sick to eat, a study says.
But researchers emphasized that acetaminophen, one of the most widely used medications for minor illness and pain, is also one of the safest when taken properly."The message is to follow the directions and be sensible in using any medication," said Dr. David C. Whitcomb, an assistant professor of medicine at the University of Pittsburgh and lead author of the study in Wednesday's issue of the Journal of the American Medical Association.
Previous research has shown that acetaminophen can damage the livers of hard drinkers at lower overdoses than in other people. But the new study shows overdoses can cause liver damage in nondrinkers if they don't get enough to eat.
Moderate overdoses of acetaminophen led to liver damage in 10 of the patients with liver damage treated at the university over 51/2 years, a review of records showed.
Eight of the 10 patients had been eating little, and three had been drinking alcohol.
One of the patients died and another required a liver transplant. The rest recovered completely.
A moderate overdose was defined as 4 to 10 grams of acetaminophen - the equivalent of eight to 20 extra-strength tablets - within 24 hours. The maximum recommended dose is 4 grams, or eight extra-strength tablets, in 24 hours.
The study also found eight additional patients who took high overdoses of acetaminophen - more than 10 grams in 24 hours - and suffered liver damage. Five had been fasting, and seven were chronic drinkers.
Two of the eight died, and one required a liver transplant.
Most of the patients fasted because illnesses made them too sick to eat, Whitcomb said. In some cases it was a severe sore throat or toothache, in others the flu or migraine headaches with nausea and vomiting.
The manufacturer of Tylenol said the study should not change the way consumers use its product.
"In the majority of cases, the overdose was combined with prolonged periods of fasting and/or excessive use of alcohol," said Johnson & Johnson, parent of Tylenol maker McNeil Consumer Products Co. of Fort Washington, Pa. "This is a rare combination of extremes that shouldn't concern the millions of people who have used Tylenol safely for more than three decades."