Drug retailers file suit to block merger facing congressional objections

Express Scripts and Medco argue that their merger would help consumers save tens of billions of dollars a year on the cost of prescription medications through lower prices and better patient adherence to treatment. 

Critics, for their part, have been able to use the political clout of pharmacies, which are in every member's district, to raise concerns about a possible loss of choice for consumers if a giant benefit manager can further squeeze drug retailers. More than 80 members of Congress so far have weighed in with their concerns.