So how do these accidental acetaminophen deaths occur? Imagine you've had major dental surgery, and your dentist prescribes a five-day supply of Percocet. You take the recommended two pills every six hours for 2,600 milligrams of acetaminophen, well below the 4,000-milligram-a-day safety threshold.
But you're still experiencing pain, so you decide to add Extra Strength Tylenol, six caplets a day for another 3,000 milligrams. Now you're feeling better but you still have trouble sleeping, so you take Nyquil, for another 650 milligrams. After a few days on this 6,250 milligram regimen, experts say acute liver damage is a real risk.
The labels on all of these products warn against mixing them. But researchers say many consumers either don't read or don't understand such warnings.
Even after taking into account people who ignore labels, there are still cases of liver damage that stump researchers. These are the people who have apparently taken about 4,000 milligrams a day or less, well within the safety threshold.
"It's still a little bit of a puzzle," says Dr. Anne Larson, of the Swedish Medical Center in Seattle. "Is it genetic predisposition? Are they claiming they took the right amount, but they really took more? It's difficult to know."
The question is critical in the lawsuits piling up against McNeil in the Eastern District of Pennsylvania, near McNeil's headquarters in Fort Washington, Pa. Virtually all of the 85 cases claim that the plaintiffs suffered liver failure despite taking Tylenol as directed.
According to one of those complaints, Madeline Speal, of Salzburg, Pa., took Tylenol for three days in November 2009 "at appropriate times and in appropriate doses." But on Nov. 28, she was admitted to Latrobe Area Hospital with catastrophic liver damage. She was then transferred to the University of Pittsburgh Medical Center where she underwent an emergency liver transplant.
The cases against McNeil, which share the same legal wording, allege that the company risked the lives of consumers by making "conscious decisions not to redesign, re-label, warn or inform the unsuspecting consuming public."
The lawsuits have been consolidated under a single federal judge to streamline the pretrial process, though they will eventually be returned to judges in their original districts for trial.
J&J and McNeil continue to reiterate that Tylenol is safe. "We remain confident in the safety and efficacy of Tylenol products, which rightfully have been trusted by doctors, hospitals and consumers for more than 50 years," McNeil said in a statement.
But lawyers for the patients suing McNeil say Tylenol can still be dangerous even when used at or just above recommended levels.
"Products that are available to consumers should have a reasonable margin of safety," said Laurence Berman, one of several attorneys representing Tylenol users.
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