Acetaminophen's maximum dose may be lowered by Health Canada

A new maximum recommended daily dose for the pain reliever acetaminophen is under consideration by Health Canada.

Acetaminophen is a medicinal ingredient in more than 470 products, including non-prescription and prescription products such as Tylenol, allergy medicines and cold relievers.

Health Canada says there are more than 4,000 hospitalizations a year in this country due to acetaminophen overdoses.

The drug is the leading cause of all serious liver injuries, including liver failure.

"We were seeing an increase in one area," said Dr. Supriya Sharma, senior medical adviser with Health Canada's health products and food branch in Ottawa.

"It wasn't a huge increase, but it was remarkable. We were seeing an increase in unintended overdoses. That was part of the impetus to move forward with the recommendations. The major thing with acetaminophen really comes down to three really simple words: use as directed."

The regulator said it will take more steps in the coming months to improve  acetaminophen safety including: 

• Add a drug facts table that will provide safety information in an easy-to-read format.
• Use plainer language, so that consumers can more easily identify products that contain acetaminophen, understand the liver risks and use the products as directed. 

Health Canada plans to hold a technical discussion with consumers and industry on other options such as:

• Decrease the maximum recommended daily dose (currently four grams per day).
• Require all children's products be supplied with a dosing device, such as a measuring cup, to prevent the risk of dosing errors (not all children's products are currently subject to this requirement). 

"Read the label," Sharma said.  

"The issue with acetaminophen has been and continues to be that it's really widely used, it's very commonly used by people and people have a history with it."

Studies showed that especially for non-prescription medications, people are quite good at reading labels, Sharma said. But when they have a history with a product, they may not necessarily be as diligent.

Consumers should know if a product contains acetaminophen, the amount to take, how frequently to take it and when to stop.

People should never exceed the maximum daily dose and avoid taking more than one acetaminophen product at a time, Health Canada advised. 

The department plans to post the draft revised standard for comments later this summer.

There will also be a public awareness campaign about safe use of the drug.

Dr. Michael Rieder, who holds a chair in pediatric pharmacology at Western University in London, Ont., said the federal government should look at combination products, where acetaminophen may not add much benefit and consumers may not be aware of its presence.

Some people metabolize acetaminophen differently, which means even a dose below the recommended daily maximum can be dangerous for them, said Dr. Muhammad Mamdani of the Li Ka Shing Knowledge Institute at St. Michael's Hospital in Toronto.