How Much Acetaminophen a Day Is Safe? Canada May Decide It’s Less
Canada’s top health agency is considering lowering the maximum recommended daily dose of acetaminophen, the active ingredient in Tylenol and other pain relievers.
Citing the risk of liver damage from overdosing on the popular pain medication, Health Canada announced it will review changes to labels, the creation of an educational awareness campaign and possible revisions to dosage recommendations.
Acetaminophen is considered safe when taken at recommended doses. Tens of millions of people use it weekly with no ill effect. But in larger amounts, especially in combination with alcohol, the drug can damage or even destroy the liver. In severe cases, acetaminophen overdose can cause death.
“Our goal is that we will have fewer effects on liver, less hospitalization, less instances of unintentional overdose, and we have more people that are informing themselves about all the products that they use, not just acetaminophen,” Supriya Sharma, senior medical adviser for Health Canada’s Health Product and Food Branch, told the Toronto Star, in an interview.
The announcement comes after the Star published a lengthy investigation last year on the potential dangers of acetaminophen. The Star, which was assisted in its reporting by ProPublica, found that acetaminophen use in Canada had been responsible for hundreds of deaths, tens of thousands of hospitalizations and tens of millions of Canadian dollars in health-care system costs over the last decade.
An earlier ProPublica investigation done in collaboration with This American Life examined the toll of acetaminophen in the United States. The investigation found that 1,500 people in the U.S. had died and tens of thousands more had been hospitalized as a result of overdosing on acetaminophen over the past 10 years.
ProPublica and This American Life also found that the Food and Drug Administration had delayed implementing safety measures for decades. McNeil Consumer Healthcare, the Johnson and Johnson unit that makes Tylenol, had worked to repeatedly block tougher safety warnings on its billion-dollar product.
Both investigations found a common problem known as “double dipping.” Acetaminophen is present in hundreds of over-the-counter medicines. Thus, people may take several medicines containing acetaminophen — say Tylenol and Theraflu — and not realize that they have exceeded the maximum recommended daily dose of acetaminophen, which is four grams, or eight 500-mg pills.
Another problem with acetaminophen: While generally recognized as safe and effective, the drug has a narrow safety margin — the dosage that can help is relatively close to the dosage that can begin to affect liver function. Some studies have suggested that liver damage can result from taking a few additional pills over the recommended daily dose for several days.
Canada and the United States are among the few industrialized nations in the world to allow unlimited access to acetaminophen. Countries such as Britain, France and Germany restrict access to the amount of acetaminophen that can be purchased, as well as the amount of medicine in an individual pill.
In response to the ProPublica story, McNeil said the company has always put consumer health first and that Tylenol is safe as long as it is used as directed.
After a 2009 FDA hearing in which experts raised new concerns about acetaminophen safety, McNeil changed the label on its Tylenol product to recommend no more than 3 grams, or six extra-strength tablets, per day.
The company maintains that acetaminophen’s safety compares favorably with other over-the-counter pain medications. (The FDA recently announced additional warnings about the risk of heart attacks of taking non-steroidal anti-inflammatory drugs, or NSAIDs, found in popular brands such as Advil.)
“McNeil takes acetaminophen overdose very seriously, which is why we have taken significant steps over the years to mitigate the risk,” the company wrote in an emailed statement.
“We will continue to work hard to educate and warn consumers of the dangers of acetaminophen overdose, reminding them to read the labels on all medicines before taking them, to take medicines only as directed and to be aware that any medicine they take has risks.”
The FDA did not respond to a request for comment on Friday. The agency has previously acknowledged that its procedure for regulating over-the-counter drugs, known as the monograph process, is cumbersome and slow. More than 38 years have passed since the FDA first began hearings on acetaminophen, and the FDA has yet to issue final guidelines on the safe use of the drug.
Last year, the agency announced that it would begin to review the monograph process in order to improve it.
It has yet to take any action.