Millions of Canadians who rely on a common heart drug are being asked to check with their pharmacist after Health Canada announced the drug may be contaminated by a carcinogen.
Health Canada said Tuesday that numerous varieties of valsartan, a generic drug sold by several companies in Canada, are being recalled over fears they are contaminated with N-nitrosodimethylamine (NDMA), a chemical that’s been classified as a probable human carcinogen by the International Agency for Research on Cancer. In a public advisory, Health Canada said Chinese company Zhejiang Huahai Pharmaceuticals supplied the valsartan to several companies that used it to make the finished product.
Health Canada first learned of the problem on June 27, but had to contact drug manufacturers and determine the scope of the problem before issuing a public advisory, a spokesperson said on Tuesday.
Valsartan is primarily used to treat high blood pressure, heart failure or for patients who have recently had a heart attack. There were more than 2.5 million prescriptions for the drugs involved in the recall dispensed in Canada last year, according to IQVIA, a company that tracks the pharmaceutical industry. That represents more than half of the total 4.4 million prescriptions dispensed for valsartan drugs in Canada, according to the IQVIA data.
The European Medicines Agency made a similar announcement last week. According to an EMA press release, the presence of NDMA “is thought to be related to changes in the way the active substance was manufactured.”
It’s unclear whether the recall will lead to a shortage of valsartan. There are companies in Canada that produce valsartan not affected by the recall, but a major portion of the drug supply was affected by the news, said Iris Krawchenko, senior pharmacist adviser with the Canadian Pharmacists Association.
Drug shortages have become an all-too-familiar occurrence in Canada in recent years, she said, posing challenges to pharmacists and patients who need access to the right medication.
“This is an unfortunate recall that can affect many patients in Canada,” Ms. Krawchenko said. “Regrettably and unfortunately, pharmacists deal with these sorts of shortages and recalls all too often.”
A June report from the C.D. Howe Institute found that about one in 10 drugs have been affected by shortages in recent years. Drug companies often cite problems with raw ingredients as the reason for the shortages.
Jacalyn Duffin, one of the authors of the report and a professor emerita at Queen’s University, said Canadians know very little about where drug ingredients come from and don’t get enough advance warning about pending shortages.
“We keep getting blindsided by products disappearing for one reason or another,” she said. “We’re always scrambling to try and find the substitutes for them.”
Health Canada is advising Canadians taking any valsartan drug to contact their pharmacist and health-care provider to determine what steps to take.
For a list of all drugs contained in the recall, check the recall and safety alert website.