One of the many proposals the Trump administration is kicking around in order to lower drug costs would shift coverage of some medicines from Medicare Part B to Part D, which is administered by private managed care plans. A new analysis, however, cautions that while government spending might be reduced, the proposal may also increase out-of-pocket costs for some beneficiaries.

How so? Let’s start at the beginning: Part B drugs are often high-priced and mostly administered by infusion or injection in physician offices. Part D drugs are purchased from pharmacies. But there is another key difference: Managed care plans can negotiate prices for Part D drugs. This is why the administration is considering moving coverage for some drugs from Part B to Part D.