Sanofi SA said on Friday it would recall popular heartburn medicine Zantac in the United States and Canada, after the medicines were linked with a probable cancer-causing impurity, Reuters reported.

The French drugmaker said it was working with health authorities to determine the level and extent of the recall, which it called a precautionary measure being taken due to possible contamination with a substance called N-nitrosodimethylamine (NDMA).

 Zantac heartburn medicine is also sold generically as ranitidine

U.S. and European health regulators said last month they were reviewing the safety of ranitidine, which is commonly sold as Zantac and its generic alternatives, after an online pharmacy called Valisure notified them that it had found impurities in the drugs.

 
The U.S. Food and Drug Administration said earlier this month it found unacceptable levels of NDMA in drugs containing ranitidine. The regulator asked ranitidine makers to conduct their own testing to assess levels of the impurity and to send samples of their products for testing by the agency.

Canada has requested drugmakers halt distribution of the drug while it gathers more information.

Read more about the timeline on Zantac HERE.