Over the next few years, the patents on seven of the 20 best-selling prescription drugs will expire. This should mean lower prices for consumers as lower cost generic drugs enter the marketplace. Generics won't necessarily lower the price immediately because the first generic approved is given six months of exclusivity in the marketplace, says Temple School of Pharmacy pharmacoeconomics expert Albert Wertheimer. "But at the end of six months, another 12 companies jump in that have been [FDA] approved and then the price goes way down."