WASHINGTON, Jan 25 (Reuters) - The U.S. Federal Trade Commission said on Monday it is filing a lawsuit against Endo Pharmaceuticals and Impax Laboratories which alleges a 2017 agreement eliminated competition between them for oxymorphone ER.

The FTC has previously filed a lawsuit against the two companies regarding the same drug, it said. (Reporting by Diane Bartz Editing by Chris Reese)