Canada will study a U.S. proposal to lower the maximum dose of over-the-counter acetaminophen, the key ingredient in Tylenol, Excedrin and other medications, a Health Canada official said Tuesday.

The Canadian move came Tuesday after a ruling by the U.S. Food and Drug Administration panel that endorsed lowering the maximum dose listed for Tylenol and dozens of other painkillers to help curb deadly overdoses.

Acetaminophen is one of the most widely used drugs in the U.S. and Canada. Many patients find it easier on the stomach than other painkillers such as ibuprofen and Aspirin, which can cause ulcers.

Panel takes aim at drugs

Government experts say prescription drugs like Vicodin and Percocet that combine a popular painkiller with stronger narcotics should be eliminated because of their role in deadly overdoses.

A Food and Drug Administration panel later on Tuesday voted 20-17 that prescription drugs that combine acetaminophen with other painkilling ingredients should be pulled off the market.

The FDA has assembled a group of experts to vote on ways to reduce liver damage associated with acetaminophen, one of the most widely used drugs in the U.S.

Panelists cited FDA data indicating 60 per cent of acetaminophen-related deaths are related to prescription products.

Despite years of educational campaigns and other federal actions, however, acetaminophen remains the leading cause of liver failure in the U.S., sending 56,000 people to the emergency room annually, according to the FDA.

FDA's experts voted 21-16 to lower the current maximum daily dose of non-prescription acetaminophen, which is four grams, or eight pills of a medication like Extra Strength Tylenol.

The group was not asked to recommend an alternative maximum daily dose.

Christelle Legault, a Health Canada official, told The Canadian Press on Tuesday that a Canadian representative is at the U.S. meetings. Over the summer, officials will analyze the comments made at the U.S. meeting and review the information presented, she said.

Warning about liver toxicity

Health Canada has developed a labelling standard for acetaminophen that includes a warning about liver toxicity, including specific information for people with serious kidney and liver disease and for alcohol users, Legault said in an email.

"It is anticipated that the draft labelling standard for acetaminophen will be finalized by September 2009," she wrote.

The FDA panel also voted 24-13 to limit the maximum single dose of the drug to 650 milligrams. The current single dose of Extra Strength Tylenol is 1,000 milligrams, or two tablets.

In a third vote, a majority of panellists said the 1,000-milligram dose should only be available by prescription.

However, some experts complained the measure would create unnecessary work for doctors and patients.

"I think the drain on the health-care system, which is already strained, would be enormous," said Dr. Robert Kerns of Yale University.

The FDA is not required to follow the group's advice, though it usually does.

Also on Tuesday, the panel rejected a proposal to pull certain cold and cough medicines off the market. The FDA says patients often pair combination drugs like NyQuil with pure acetaminophen treatments like Tylenol, exposing themselves to unsafe levels of the drug.

The panel cited FDA data that said the medications play a minor role in acetaminophen overdoses, with only 10 per cent of acetaminophen-related deaths involving a cold and cough product.

A recall of combination cold medicines could have cost manufacturers hundreds of millions of dollars in revenue.