(Reuters) - Health Canada said on Wednesday four more companies were recalling heartburn drug ranitidine, commonly known by its brand name Zantac, after presence of a probable cancer-causing impurity was found in some of the drugs.

The companies recalling the drugs include Apotex Inc, Pro Doc Limitée, Sanis Health Inc and Sivem Pharmaceuticals ULC, along with Novartis AG's recall, which was announced last week.

Health Canada said the lots of the medicines being recalled may have been made using an active ingredient containing the impurity, N-nitrosodimethylamine (NDMA), above accepted levels.

NDMA is one of the impurities that has been found in blood pressure and heart failure medicines called Angiotensin II Receptor Blockers (ARBs), which regulators have been recalling since last year.

U.S. and European health regulators said earlier this month they were reviewing the safety of ranitidine. Canada last week requested makers of the drug to halt distribution as it gathers more information.

Branded versions of the drug such as Sanofi SA's Zantac are available for over-the-counter (OTC) sale in Canada, while generic versions are available for sale both OTC and with prescription.





(Reporting by Manas Mishra in Bengaluru; Editing by Shounak Dasgupta)