In signing an executive order aimed at reducing U.S. drug prices, President Donald Trump said some prices would be cut in half or more "almost immediately." But the order is light on details of how the plan would be implemented.

Countries with universal healthcare systems have stronger bargaining power, which has allowed them to effectively negotiate lower drug prices.

The president has long complained that the United States pays more for medicines than other wealthy countries. But he offered no clear legal authority to mandate lower prices.