President Donald Trump said his executive order on drug prices would lower some prices in half or more. But the details are scant.

Experts said Trump’s action could potentially lower the cost of prescription drugs, perhaps by the 30 percent to 80 percent scale Trump said, but they cautioned that the order’s required procedural steps would make it far from an immediate fix.

US President Donald Trump’s effort to reduce drug prices for Americans relies on a practice long employed in Europe: aligning costs with lower prices paid elsewhere. If he succeeds, the knock-on effect could hit Europe hard.