Canada May Follow Australian Lead With Black box Warnings For Painkiller DrugsFeb 15, 2005 | Canadian Press
Health Canada may follow Australia's lead and put special warnings and dosage limits on the remaining painkillers in the now-controversial class of drugs known as Cox-2 inhibitors, Health Minister Ujjal Dosanjh said Tuesday.
Dosanjh also suggested he might consider following the lead of the new U.S. secretary of health and establish an independent drug agency to monitor the safety of drugs once they hit the market an idea to which he had been previously cool.
"I'm not unalterably opposed to the idea of an independent drug agency," Dosanjh said in a media teleconference on the eve of the start of pivotal U.S. Food and Drug Administration hearings into the safety of Cox-2s such as Celebrex and Bextra as well as other painkillers.
The hearings, which will be closely watched by regulatory agencies around the globe, were called in a bid to clear the confusion that has reigned among doctors and patients since Sept. 30, when drug giant Merck announced it was pulling its blockbuster arthritis drug, Vioxx, because of evidence it increased the risk of cardiac problems in some users.
Regulatory agencies such as the FDA and Health Canada have come under fire since then, with critics suggesting they do not move quickly enough to protect the public in the face of evidence of adverse events linked to prescription drugs.
The new U.S. health secretary, Mike Leavitt, announced Tuesday what he called an "independent" drug safety oversight board, made up of scientists from the FDA and other government agencies.
Dosanjh also moved to repair cracks in the public confidence, saying his department would set up a panel drawn from internal and external experts to advise the department on drug safety issues and would consider an independent drug safety board if it was required to ensure public confidence in the regulatory process.
He also promised more public input into the drug regulatory process.
"Canadians have and must continue to have confidence in Health Canada to act in their best interests," the minister said.
"One of the means to accomplish this to ensure opportunities for public input before regulatory decisions are made, that means before approval and in the post-market actions."
On the issue of future regulatory action on Cox-2s, Dosanjh said an extensive review of the drugs by 10 scientists in his department should be concluded within six to eight weeks. At that point, recommendations will be made and the public will be given an opportunity to provide input, department officials said.
Even before then, Health Canada may follow the lead of Australia, which announced Tuesday it would require Cox-2 drug labels to carry special "black box" warnings. Dosanjh said he would direct Health Canada officials to take similar actions, if their deliberations supported such a move.
A series of studies published since Vioxx was pulled from the market has suggested the problems associated with it might actually cross the entire class of drugs, the Cox-2s which swept the market after they were introduced in the late 1990s.
Though much more expensive than traditional over-the-counter painkillers known as NSAIDS (non-steroidal anti-inflammatory drugs), the Cox-2s were touted as protecting the lining of the stomach, thereby reducing the risk of gastric bleeding associated with older pain medications.
While much of the safety evidence around Cox-2s has been conflicting, some including the influential New England Journal of Medicine now argue the risks associated with these drugs may outweigh their benefits.
"Because there are well established options for treatment of all the approved indications for these drugs, it is reasonable to ask whether the use of the drugs can now be justified," journal editor Dr. Jeffrey Drazen wrote in an editorial that will appear in the March 17 issue but was released Tuesday to coincide with the start of the hearings.
Others believe at least one of the remaining Cox-2s, Celebrex, can safely be used by people not at high risk of cardiac problems, as long as they don't take high doses more than 200 milligrams a day. The studies that found problems involved subjects taking as much as 800 mgs a day, a dose doctors wouldn't be expected to prescribe.
"To me what makes the most sense is there probably is a risk but it's probably at the very high doses that nobody in their right mind would use," said Dr. Muhammad Mamdani, an expert on Cox-2s based at the Institute for Clinical Evaluative Sciences in Toronto.
Mamdani argues drugs that have been highly effective and safe for some users should not be junked based on incomplete and selective analysis of scientific data.
Dr. Mark Fendrick agreed.
Fendrick said his view of the safe use of Cox-2s hasn't changed since questions about their safety started to surface.
"Give it to people who are likely to benefit from the GI (gastro-intestinal) perspective, which is why the drugs were developed," said Fendrick, an internal medicine specialist at the University of Michigan.
"For those at risk of cardiac problems or taking aspirin to prevent them consider a traditional NSAID with a gastro-protective agent, such as a proton-pump inhibitor."
That combination will provide equivalent pain relief and similar levels of protection for the stomach, he said.