A new study has raised more red flags about Avandia, a widely-used drug for patients with Type 2 diabetes, finding it carries a higher risk of heart failure and death than a similar drug.
The findings prompted researchers to conclude Avandia should no longer be prescribed.
Avandia, or rosiglitazone as it's known generically, was once heavily promoted for Type 2 diabetes because it helps to lower blood-sugar levels in patients. But the medication and other members of the drug class known as thiazolidinediones, or glitazones, can cause fluid retention and sometimes heart failure in some patients.
Avandia's heart risks were brought to light two years ago in a medical journal article that reported a 43 per cent higher risk of heart attacks among Avandia patients when compared with those taking other diabetes drugs.
As a result, Avandia use dropped sharply, but tens of thousands of Canadian patients still take it. Others have switched to Actos, another glitazone. But questions about whether Actos is safer than Avandia have remained.
This latest study by the Institute for Clinical Evaluative Sciences (ICES) finds Avandia does carry a higher risk of heart failure and death.
The study, published \ in the British Medical Journal, looked at 39,494 patients older than 66 who started taking either Actos or Avandia between 2002 and 2008. It found that Actos users had a 23 per cent lower risk of hospitalization for congestive heart failure than Avandia users, as well as a 14 per cent lower risk of death from any cause. The risk of heart attack was about the same in both groups.
The researchers estimate that one additional hospitalization for heart failure every year would occur for every 120 patients treated with Avandia rather than Actos, and one additional death would occur for every 269 patients treated with Avandia rather than Actos.
Worldwide, switching 1 million patients from Avandia to Actos would prevent 3,700 deaths and 8,300 people from going to hospital.
Although the American Diabetes Association recently advised against prescribing Avandia, it remains widely used in Canada, with more than 650,000 prescriptions filled last year. The Canadian Diabetes Association still recommends both drugs for diabetes treatment.
The study's principal investigator and ICES Scientist, Dr. David Juurlink, wonders whether that's good advice especially since Avandia has no therapeutic advantages over Actos.
"I think there are enough red flags regarding the safety of Avandia that it's a reasonable question to ask whether this drug should be sold at all," Juurlink tells CTV News.
"I certainly don't prescribe it, I would never take the drug, and it's not clear to me why any other physician would want to prescribe it to a patient."
Raymond Wagner, a Halifax-based lawyer who is planning a class-action suit on behalf of his Nova Scotia clients, said there may have been concerns about the drug from as far back as 1999.
"I think Health Canada, and I think physicians prescribing the medication, should look to the studies that are pointing in this particular direction and make some serious considerations about changing the medication," he told CTV News.
Many diabetes specialists say they no longer prescribe Avandia to new patients.
"If it's working well, then there may be a reason to stay on it; but, if it's not, then it's time to re-evaluate and it may be time to switch to something else," says diabetes specialist Dr. Baiju Shah.
With a report from CTV medical specialist Avis Favaro
