Medicare Part D prescription drug plans are also known as PDPs. These are standalone plans that can be purchased through private insurance companies. PDPs provide coverage for prescription drugs and medications, and may also cover some vaccines too.
Medigap plans, also called Medicare supplement insurance plans, cover some of the costs not paid by Original Medicare (Parts A & B). For example, Medicare Part B typically pays 80 percent of the cost for a covered service, such as a doctor visit. You would be responsible for the other 20 percent of the cost, which a Medigap plan may cover.
Original Medicare (Part A and Part B) doesn’t cover everything. Some people choose to buy Medicare supplement insurance (also called Medigap) to help pay some of the expenses that Medicare doesn’t pay.
The Part D coverage gap – or “donut hole” – is a payment stage with Medicare prescription drug plans and a budget concern for many people. It’s a period of time when the main cost burden for prescription drugs shifts from the plan to the plan member.