FDA Clamps Down On Acetaminophen In Prescription Drugs

Narcotic painkillers Vicodin, Lortab and Percocet contain a potentially dangerous ingredient that most people rarely think about: Acetaminophen.

That's right, the same medicine sold separately as Tylenol is often combined with narcotics to make even more potent pain pills. But, as the Food and Drug Administration noted today, too much acetaminophen can ruin a person's liver.

So the agency is asking makers of prescription drug combinations that contain acetaminophen to limit it to 325 milligrams per pill, capsule or slurp of liquid medicine a person might take.

The drugs will also have to carry stern warnings about the dangers of acetaminophen overdoses for livers, something over-the-counter medicines already are required to do.

How big a factor is acetaminophen in liver failure? Well, the FDA cites a study from a few years back that found acetaminophen overdoses (about half of which were unintentional) were to blame for more than 40 percent of cases of acute liver failure examined over six years.

People can get into trouble taking too much of the painkillers or inadvertently taking the medicines along with other acetaminophen-containing remedies. The FDA's announcement includes a rundown of common medicines affected.

It's worth noting that Vicodin and generic versions (hydrocodone plus acetaminophen) are the most prescribed medicines in the United States, according to data from IMS Health. Pharmacists dispensed more than 128 million prescriptions for the stuff in 2009.