Drug pricing watchdogs worry President Donald Trump's plan to assess 100% tariffs on some imported brand name drugs could lighten patients pocketbooks.

But that fate is far from certain, given caveats the Trump administration announced as part of a sweeping April 2 order on tariffs for imported brand name pharmaceuticals.

Drugmakers that agree to move production to the United States will face a 20% tariff while they transition and no tariff if they also agree to lower prices to “most favored nation” levels paid by other countries, according to the order. The full tariff will be levied if drug production isn’t in the U.S. in four years.

The tariffs assessed to larger drug companies will take effect July 31 unless companies commit to price concessions and bolstering domestic manufacturing. Smaller drug manufacturers will have until Sept. 29 to comply.

Merith Basey, CEO of Patients for Affordable Drugs, warned that terms of the most favored nation drug pricing deals already announced have "not delivered meaningful savings for the vast majority of American patients."