A Quebec pharmaceutical company has recalled two lots of a heart attack and stroke medication contaminated with a cancer-causing impurity.

Health Canada issued a statement Thursday advising Canadians that Laval-based Pro Doc Limitée voluntarily recalled the lots of irbesartan tablets, which were only distributed in Quebec. Irbesartan is a sartan medicine used to treat patients with high blood pressure or those who have had heart failure or a recent heart attack.

“There have been multiple recalls of products containing other sartans in Canada and internationally since July 2018 because of nitrosamine impurities,” said Health Canada in the statement.

The nitrosamine impurity, N-nitrosodiethylamine (NDEA), found in the drugs is a “probable human carcinogen,” meaning the risk of cancer increases after “long-term exposure.”

“Health Canada is advising that there is no immediate risk to patients taking these medications, since the potential risk of cancer is with long-term exposure to the impurities that exceed safe levels,” said Health Canada. “Patients should not stop taking their medication unless advised to do so by their health care provider.”

The agency encouraged Canadians to visit the online database drugshortagescanada.ca for more information on drugs that have been discontinued, adding that there are alternative products to the irbesartan tablets currently available on the Canadian market.