Holdings Inc., which makes painkiller Zohydro and other medications, has filed for bankruptcy protection after drug sales to consumers fell below expectations. It blamed a revenue drop partly on fresh competition with generic versions of its migraine treatment Treximet. In documents filed in U.S. Bankruptcy Court in Wilmington, Del., company officials said they already have a $76 million offer from affiliates of Highbridge Capital Management LLC, which offered to pay cash and forgive some of its debt.