Pain killer dose under review
Health Canada aims to reduce the strength of acetaminophen drugs
Health Canada is considering dramatically reducing the daily recommended dosage of the popular pain killer acetaminophen in light of growing concerns about liver damage resulting from accidental and intentional overdoses, Postmedia has learned.
The federal health department is looking at reducing the daily recommended dose of acetaminophen — commonly sold as Tylenol but also contained in other products — from the current four grams to 2.6 grams per day. That is the equivalent of about five Extra Strength Tylenols a day, compared with the current recommendation of eight Extra Strength Tylenols.
It is also considering limiting the amount of acetaminophen per tablet, from the current maximum of 500 to 350 milligrams, effectively doing away with the product sold as Extra Strength Tylenol. Some patients have reported liver injury below the current daily recommendations, according to doctors.
In a closed-door meeting, Health Canada officials met with experts and stakeholders Tuesday to discuss the impact of the proposed changes. A decision on the risk minimization options is expected this summer.
Gerry Harrington, vice president of policy and regulatory affairs at Consumer Health Products Canada, which represents the industry, said there is “a lot of pushback” to the idea of reducing maximum doses and 500 milligram tablets. “Health Canada has not presented any evidence to suggest that is going to have any impact on behaviour.”
He said the industry is not alone in opposing the proposal to remove 500 milligram tablets of acetaminophen, which makes up 90 per cent of Tylenol sales.
“Taking away a pain relief option like that right now is not supported by patient groups.” Education, he said, is the key to safety.
Health Canada is also looking at labelling changes to help prevent people from taking too much acetaminophen, something that leads to more than 4,000 hospitalizations a year in Canada. There are 250 cases of serious liver injury a year in Canada, half of them unintentional.
Acetaminophen is the leading cause of all serious liver injury, including acute liver failure, in Canada, which sometimes results in liver transplants or death.
More than four billion doses of acetaminophen are sold in Canada every year.
Health Canada says it is “generally recognized” that doses above 10 grams a day in adults damage the liver.
But there have also been reports of liver injury at doses below the recommended maximum. As many as 20 per cent of acetaminophen-related liver injuries reported to Canada Vigilance (which monitors adverse drug effects) were from doses within the recommended range. In many of the cases, patients had conditions affecting the liver.
Dr. Eric Yoshida, a professor of medicine at the University of British Columbia who is part of the liver transplant program at Vancouver General Hospital, said he routinely sees patients experiencing acute liver failure — or suffering from severe liver damage — because of acetaminophen. One of his patients, he said — a young construction worker who suffered aches and pains as a result of his job — died after inadvertently taking too much acetaminophen.
Yoshida, who works with the Canadian Liver Foundation, called proposed changes to acetaminophen doses “common sense.”
“If we could save one person from having a liver transplant that they wouldn’t otherwise have needed, or prevent one person from dying, it would be worth it.”
Acetaminophen is wildly popular on its own, under the brand name Tylenol and other brands, as well as in combination with other products, such as cold and cough medications or narcotic pain relievers such as codeine. People can often take more than they realize by combining several products containing acetaminophen.
When taken as directed, it is considered safe. But its ubiquity, the ready availability of large amounts of it, combined with the fact that it has what is known as a narrow therapeutic window — meaning the difference between a safe dose and an unsafe dose is not huge — have increasingly raised concerns about its safety.
“I think if Tylenol was brought to the market today, it would not be approved because of its toxicity,” said Dr. David Juurlink, head of the division of Clinical Pharmacology and Toxicology at Sunnybrook Health Sciences Centre in Toronto.
A spokeswoman for Johnson and Johnson — the company that makes Tylenol — noted that Health Canada, in a 2015 summary review, called acetaminophen safe and effective when used as directed.
“As the makers of Tylenol, we actively promote the responsible use of all over-the-counter medications, which begins with reading the label and following the dosing directions. We share Health Canada’s commitment to health and safety and fully support ongoing education as the most effective way to encourage Canadians to use all medication as directed.”
The company has created two websites — getreliefresponsibly.ca and knowyourdose.org — to promote responsible use of acetaminophen.
Ottawa physician Kapil Khatter, who wrote a blog post encouraging tighter restrictions on acetaminophen, said packaging changes that limit how much you can buy at a time, could reduce injuries and deaths related to liver damage from too much acetaminophen.
And because other painkillers, such as aspirin and ibuprofen, are associated with bleeding ulcers, Khatter believes acetaminophen should remain a “go-to” non-prescription painkiller, as long as stronger action is taken to reduce harm.
Juurlink said there are many unknowns about the effects of acetaminophen, including on brain function, but taking it off the market “is not going to happen.” Still, he said, “I don’t think the world would be a worse place,” if it were.