Another Pain Pill Under Suspicion
Study links naproxen to higher heart attack, stroke riskDec 22, 2004 | The Ottawa Citizen Another popular painkiller used by hundreds of thousands of Canadians is being linked to an increased risk of heart attack and stroke, sending regulators and doctors scrambling to make sense of the data and leaving patients wondering, "What now?"
The drug, naproxen, has been prescribed to Canadians with joint and other body pain for 30 years. With more than 2.3 million prescriptions filled in Canada this past year, naproxen is among the most common prescription drugs chosen by doctors switching patients off Vioxx or Celebrex, two painkillers recently suspected of causing heart problems.
Now, U.S. health officials have abruptly suspended a large Alzheimer's prevention study after investigators found a 50-per-cent increased risk of heart attack and stroke among patients taking naproxen, versus those on a placebo or "dummy pill."
A leading Canadian rheumatologist called the surprise preliminary findings "so far out there, it doesn't make any sense." If anything, naproxen and other older, non-steroidal anti-inflammatory drugs (NSAIDs) were thought to protect the heart by making platelets less sticky, reducing the risk of a blood clot forming and lodging in an artery.
"But this (Alzheimer's study) is saying the exact opposite. This is suggesting it is increasing the risk, and it doesn't make sense," said Dr. Doug Smith, head of the division of rheumatology at the Ottawa Hospital.
"I think what people should not take away from this is that taking naproxen is going to cause heart attacks. It's way far from proven."
But a Canadian drug expert says the findings call into question the heart safety of other older, non-steroidal painkillers, including ibuprofen.
"I don't think anyone has taken a careful look at the older, traditional drugs," says Dr. Muhammad Mamdani, head of the drug research group at the Institute for Clinical Evaluative Sciences and associate professor at the University of Toronto.
It's already known naproxen and other older anti-inflammatories can cause ulcers and life-threatening gastrointestinal bleeds. It was exactly because of these toxic effects on the stomach that Vioxx and other drugs in the COX-2 class were developed five years ago.
"We don't have good information on ibuprofen in terms of cardiovascular outcomes. Can we assume that it's safe? We certainly need more information," says Dr. Mamdani.
Naproxen, sold over the counter in the U.S. under the brand name Aleve, has been available in Canada since 1974 by prescription only, with 27 brand name and generic products, including Roche Canada's Naprosyn.
Health Canada said yesterday it's reviewing the new naproxen data. In the meantime, patients taking the pain pills should follow instructions on the label and use the lowest dose to control symptoms, an official said. Dr. Supriya Sharma also said NSAIDs should not be used in patients with "compromised cardiac function."
"We're not taking this lightly. It's new information and we will take it seriously," said Dr. Sharma, associate director general of the marketed health products directorate.
She cautioned it's not known whether the increased risk of heart and stroke in naproxen users is statistically significant. As well, the Alzheimer's trial involved patients aged 70 and older, who may have other risk factors for heart disease.
The National Institutes of Health Alzheimer's trial was testing whether naproxen or Celebrex could reduce the risk of the brain disease in people who had a family history of Alzheimer's, but no symptoms.
While it's creating fresh headaches for doctors, there is some possible good news for Celebrex users, who were warned just days ago that one of two trials testing Celebrex as a treatment for colon cancer found patients taking high doses between 400 to 800 milligrams a day had 2.5 times the risk for heart attacks, strokes, blood clots and other cardiovascular events as those taking placebo.
The Alzheimer's trial found no significant increased risk of heart attack or stroke in patients taking Celebrex in doses of 200 mg twice daily.
The news sent shares of Pfizer Inc., Celebrex's manufacturer, up almost three per cent yesterday. The stock rose 68 cents U.S. to close at $24.97 U.S. in New York. The company had lost about $30 billion U.S. in market capitalization since results from the cancer trial were released Friday.
Pfizer says the latest data are consistent "with the large body of Celebrex scientific evidence that has accumulated over 10 years in more than 40,000 patients" and that the drug remains an option for arthritis and acute pain "at the lowest effective dose for appropriate patients."
The FDA this week asked Pfizer to halt all consumer advertising of Celebrex while it reviews the cancer trials. In September, Vioxx, another COX-2 inhibitor once promoted as a "super Aspirin," was pulled from the market in the largest drug recall in history after studies linked it to an increased risk of heart attack and stroke.
In the new U.S. government-funded study study, about 2,400 people were randomly assigned to receive naproxen, Celebrex or a placebo for up to three years.
In all, 70 people experienced either a heart attack or stroke. An early review of the data showed an "apparent increase" in risk in those taking 220 mg twice a day of naproxen compared to placebo.