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Which Medicare Part D prescription drug plan should I choose?

Louise Norris | November 11, 2022

Reviewed by our health policy panel.

Q: Which Medicare Part D prescription drug plan should I choose?

A: Selecting your Medicare Part D prescription drug coverage is an important decision, and one that you need to reconsider every year. There’s a lot that goes into this, so let’s consider some basics to keep in mind:

What's the difference between a PDP and an MAPD?

Medicare Part D coverage is provided by private health insurance carriers, but it can be purchased as a stand-alone Part D prescription drug plan (PDP) or integrated with a Medicare Advantage plan, known as a Medicare Advantage prescription drug (MAPD) plan.

There are PDPs available in all areas of the country, and this is what you need if you have Original Medicare and don’t have supplemental drug coverage from another source (such as an employer’s plan or a retiree plan). If you prefer Medicare Advantage (to take the place of Original Medicare), there are Medicare Advantage plans available in nearly every area of the country for 2023, and 89% of them are MAPDs.

When can I enroll in Part D coverage?

You can enroll in Part D coverage when you first enroll in Medicare. And you’ll also have an annual opportunity during Medicare open enrollment — from October 15 to December 7 —to either enroll in Part D coverage for the first time, or to switch to a different PDP or MAPD.

If you don’t sign up for Part D (either a PDP or MAPD) when you’re first eligible, you could end up paying a late enrollment penalty when you eventually do sign up for Part D, assuming you didn’t have creditable drug coverage from another source during the time you delayed your enrollment. And if you end up with a late enrollment penalty, you’ll have to continue to pay the penalty for as long as you have Part D coverage. The amount of the penalty depends on how long you went without creditable drug coverage, so the longer you wait to enroll in Part D, the larger the penalty gets.

Each year between October 15 and December 7, you have an opportunity to review the PDPs and Medicare Advantage plans (most of which are MAPDs) that are available in your area, and switch to a new one if you choose to do so.  If you join a PDP or MAPD plan between October 15 and December 7, your prescription drug coverage takes effect January 1.

What factors are important when choosing Part D coverage?

There are several things to keep in mind when you’re choosing your part D coverage, including the total cost (premium plus out-of-pocket costs) and whether you prefer Original Medicare or Medicare Advantage, since that’s the first step in deciding whether you’ll need a PDP or an MAPD. (Here are some factors to consider when you’re deciding between Original Medicare + Medigap + a PDP versus Medicare Advantage).

For both PDPs and MAPDs, it’s important to keep in mind that formularies (the covered drug list) can change from one year to the next, so the plan that presented the best value this year might not be the best value next year. In addition, premiums can change from one year to the next, making a plan a better or worse value when compared with the other available options for the coming year.  The plan with the lowest premium doesn’t necessarily provide the best value, because you may incur higher out-of-pocket costs when you get your medications. has a plan finder tool that lets you enter the medications you take and it will help you sort through the PDPs and MAPDs in your area to determine which ones will provide the best coverage based on your own prescription needs. After entering your medication list, you will be asked to choose a pharmacy. It’s important to choose multiple different retail pharmacies and mail-order options when you’re comparing plans. Pricing is determined by all three factors: prescription, insurance company, and pharmacy acquisition cost.

You can also create an account at, which will pre-populate your medication list for you. Just be sure to remove any one-time prescriptions such as antibiotics.

It’s important to repeat the plan comparison process each year during open enrollment, even if your medications haven’t changed – because the formularies and out-of-pocket costs for the available PDPs may have changed, along with their premiums.

If you don’t take any medications, you will want to confirm the preferred pharmacies, just so that if you do need a prescription, you will know which pharmacy will have the lowest price.

Other points to keep in mind:

Medicare Advantage plans have maximum out-of-pocket limits that can’t exceed $8,300 in 2023 for in-network services. But it’s important to note that prescription costs don’t count towards the out-of-pocket cap, since it only applies to services that are covered under Medicare Parts A and B.

For the time being, there is no cap on out-of-pocket costs under Part D, regardless of whether it’s a PDP or MAPD. But that will change as a result of the Inflation Reduction Act, starting in 2024 (and a lower Part D out-of-pocket cap will apply starting in 2025).

Prescription drug assistance for enrollees with low incomes

Be sure to check your eligibility for Extra Help. Each year, thousands of seniors who are eligible do not apply and do not get the help with premiums, deductibles and copays they are eligible for. And as of 2024, the Inflation Reduction Act will increase the income and asset limits for full Extra Help, expanding this valuable benefit to more people.

Read more here about assistance programs for people who have Medicare.

Louise Norris is an individual health insurance broker who has been writing about health insurance and health reform since 2006. In addition to her coverage of the individual/family market, she has written dozens of opinions and educational pieces about Medicare coverage for 

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