The next great pharmaceutical multidistrict litigation may have arrived — in the form of thousands of claims against the prescription pain medications Darvon and Darvocet, which the manufacturer recalled under government pressure about two months ago.

Since Dec. 3, seven lawsuits have been filed in federal court alleging that Xanodyne Pharmaceuticals Inc., the manufacturer of Darvocet and Darvon, knew of the risks but failed to warn doctors and the general public that the medications could contribute to heart disease. The suits, some them class actions, were filed on behalf of people who suffered from heart problems or died after taking the drugs.