Tylenol found to cause liver damage even in small doses

NewsTarget
Jul. 05, 2006

Healthy adults who took the maximum dose of Tylenol for two weeks were found to have liver damage, according to a study appearing in the latest issue of the Journal of the American Medical Association.

Researchers instructed 106 study participants to take 4 grams of Tylenol (eight extra-strength tablets) a day for two weeks, with some taking only Tylenol, and some taking Tylenol combined with an opioid painkiller. The rest of the participants were given a placebo.

Nearly 40 percent of the participants taking Tylenol or the Tylenol/opioid combination displayed abnormal liver test results that indicated liver damage, while those taking the placebo showed no damage.

The study's co-author, Dr. Neil Kaplowitz of the University of Southern California said, "I would urge the public not to exceed 4 grams a day. This is a drug that has a rather narrow safety window." Kaplowitz added that heavy drinkers should not exceed 2 grams a day.

Tylenol maker McNeil Consumer & Specialty Pharmaceuticals said it had conducted its own research that tracked high-dose Tylenol users over longer periods than the Kaplowitz study, and found that its product did not lead to liver disease.

Kaplowitz and co-author Dr. Paul Watkins of the University of North Carolina were hired by Purdue Pharma, which makes the prescription painkiller OxyContin, to see why people testing a drug containing acetaminophen and the opiate hydrocodone were having abnormal liver tests. Contrary to the researchers' theories, they found that acetaminophen was the culprit.

Acetaminophen is Americans' over-the-counter painkiller of choice. Acetaminophen overdose is also the leading cause of acute liver failure.