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Medicare prescription drug coverage

There are two types of plans you can choose from that offer Medicare Part D coverage. They are prescription drug plans (PDPs) and Medicare Advantage prescription drug plans (MAPDs). Expand each question below to learn more about Medicare Part D coverage.

Medicare prescription drug coverage (Part D) is offered through private insurance companies, like Aetna®. You can get Part D coverage through either:


  • A stand-alone prescription drug plan (commonly referred to as a PDP)
  • A Medicare Advantage prescription drug plan (commonly referred to as a MAPD)

A prescription drug plan (PDP) is a stand-alone Medicare Part D plan. PDPs only offer Part D and work together with your Original Medicare. This is a good option for someone who wants to stay in Original Medicare but add prescription drug coverage.

You are eligible to enroll in a PDP if you are already enrolled in Medicare Part A and/or Medicare Part B. Medicare Part D prescription drug plans are only available through private insurers such as Aetna®.


For more information, please visit our Unpacking Medicare prescription drug coverage page.

A Medicare Advantage prescription drug plan (or MAPD) is a plan that includes medical and prescription drug coverage. MAPD plans are only available through private insurers like Aetna®.


An MAPD plan includes:


  • Medicare Part A (hospital)
  • Medicare Part B (medical)
  • Medicare Part D (prescription)

Like other health plans, MAPDs come in various forms, such as HMOs (health maintenance organizations) and PPOs (preferred provider organizations).

There are four phases of Medicare Part D coverage you may enter in a plan year. What you pay for covered prescriptions may change as you move through the phases. Coverage phases do not affect monthly premium amounts.


  1. The annual deductible phase — You begin in this phase (if your plan has a deductible). You pay the full cost of your covered prescriptions until you meet your plan’s deductible amount (up to $545 in 2024). The process of meeting the deductible starts over again at the beginning of each year.

    Keep in mind, some deductibles may only apply to drugs on specific tiers.

  2. The initial coverage phase — This is the phase after you have met your deductible (if it applies) and before your total drug costs have reached the initial coverage limit amount (up to $5,030 in 2024). In this phase, you pay a copayment or coinsurance for each covered prescription you fill until your total drug costs reach the initial coverage limit.

  3. The coverage gap phase (donut hole)  —This begins after your total drug costs for covered prescription drugs reaches the initial coverage limit amount (up to $5,030 in 2024). In this phase, you’ll pay no more than 25% of the cost for covered brand or generic prescription drugs. This phase ends when you have spent enough to qualify for catastrophic coverage ($8,000 in 2024).

    Some people will never enter the coverage gap because their drug costs won’t be high enough.

  4. The catastrophic coverage phase — You move from the coverage gap to this phase if your out-of-pocket drug spending for the year reaches $8,000 in 2024. In this phase, the plan pays the full cost of your covered Part D prescription drugs and you'll pay a $0 copay for the rest of the year.

Note: The excluded drugs covered by some of our plans as an enhanced benefit — such as prescription vitamins — will be a $0 copay at preferred pharmacies in this phase. At standard pharmacies, initial coverage phase cost-sharing will apply.

  • Each plan has a formulary (drug list) showing which drugs it will cover, the tier a drug is on, any limits or requirements and mail-order availability.
  • Both generic and brand drugs are covered under Part D. Visit our formulary FAQ page to learn more.
  • A generic drug is a prescription drug that is approved by the Food and Drug Administration (FDA) as having the same active ingredient(s) as the brand-name drug. Generally, a “generic” drug works the same as a brand-name drug and usually costs less.
  • A brand-name drug is a prescription drug that is made and sold by the company that originally researched and developed the drug. A brand-name drug has the same active ingredients and formula as its generic version.


Here are some examples of what Part D prescription drug plans do not cover:


  • Drugs given in hospitals or doctors’ offices that are already covered under Part A or Part B
  • Any drugs not listed on a plan’s drug formulary (except in special circumstances)
  • Non-prescription drugs or prescription vitamins (other than prenatal vitamins). Other examples include weight loss or weight gain, hair growth and/or erectile dysfunction drugs.

ⓘ SilverScript® Plus (PDP) and some of our MAPD plans include coverage for some excluded drugs not normally covered by Medicare Part D. This includes a variety of prescription vitamins and generic erectile dysfunction drugs.


For a more complete list of drugs not covered by Medicare, please visit our Prescription drug formulary FAQ page.

Yes. Part D, in general, covers recommended adult vaccines when needed to prevent illness.
Under the Inflation Reduction Act, most Part D vaccines recommended for adults (ages 19 and older) given to prevent an illness now have a $0 copay. Vaccines eligible for the $0 copay include those recommended by the Centers for Disease Control and Prevention (CDC) Advisory Committee on Immunization Practices (ACIP). This includes the shingles vaccine.
Check the formulary (drug list) for a list of covered vaccines. And talk to your provider about which ones are right for you.

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