 Insurance companies' lists of covered drugs, called formularies, are shrinking. On average, Medicare formularies only cover a little more than half of the drugs approved by the FDA. But in 2010, they covered nearly three-quarters of them. That's according to new research by GoodRx, a website that helps patients find discounts on prescription drugs. GoodRx is an NPR funder. Here's Tori Marsh, the director of research at GoodRx. Far too often, people talk about