Bristol-Myers Squibb Co. and Sanofi-Aventis SA said Monday they filed an injunction against Apotex Corp. to stop the Canadian drug maker from selling a less expensive, generic version of the blood thinner Plavix. They also said they have begun discounting Plavix to stem the loss of the drug’s market share.

A hearing on the motion is set for Friday in the U.S. District Court for the Southern District of New York, where the injunction was filed and a patent case on Plavix is pending.