- How Pricey Is Your Drug? These 10 Sold the Most in the U.S. Last Year Stat by Max Blau — A whopping $450 billion was spent in the United States on prescription drugs last year. Topping the list, perhaps unsurprisingly, are medications whose patents were still in force or had recently expired. When a patent expires, generic versions — or biosimilar versions of biologic drugs — can become available, driving down costs that in turn make them accessible to more patients.