Medicare Part D prescription drug coverage FAQs

Medicare drug coverage (Part D) is offered by private insurance companies, like Aetna®. You can get Part D in two ways:
 

• A stand-alone prescription drug plan (PDP)
• A Medicare Advantage plan with drug coverage (MAPD)

Learn more about how Part D plans work

A PDP is a stand-alone Medicare Part D plan that only covers drugs. It works with your Original Medicare (Parts A and B). This is a good choice if you want to stay in Original Medicare but add prescription drug coverage.
 

You can join a PDP if you have Medicare Part A and Part B or both. Only private insurers, such as Aetna®, offer PDPs.

An MAPD plan includes medical and drug coverage. MAPD plans are only available through private insurers like Aetna®.

An MAPD plan includes:
 

• Hospital care (Medicare Part A)
• Medical care (Medicare Part B)
• Prescription drugs (Medicare Part D)

Like other health plans, MAPDs come in different types, such as health maintenance organization (HMO) plans and preferred provider organization (PPO) plans.

Each plan has a drug list (formulary). This list shows which drugs are covered, the tier a drug is on, any limits and if it can be ordered by mail. You can read our formulary FAQs to learn more.

Both generic and brand drugs are covered under Part D.
 

• A generic drug works the same as a brand-name drug but usually costs less. It has the same active ingredients.
• A brand-name drug is made and sold by the company that first created it. It has the same active ingredients as its generic version.

Here are some things that Part D drug plans don’t cover:

• Drugs given in hospitals or doctors’ offices that are already covered under Part A or Part B
• Drugs not listed on your plan’s drug list (except in special cases)
• Nonprescription drugs and most vitamins (other than prenatal vitamins)
• Medicines like those for weight loss, hair growth and erectile dysfunction drugs

Learn more about which drugs are not covered by Medicare

There are three phases of Medicare Part D coverage you might go through in a plan year.

What you pay for covered prescriptions may change as you move through the phases. The phases don’t affect your monthly premium.

1. Annual deductible phase — You start here if your plan has a deductible. You pay the full cost of your covered drugs until you meet your plan’s deductible (up to $615 in 2026). Only costs for covered drugs count toward your deductible. This phase starts over each year.
   
   Keep in mind, some deductibles may only apply to drugs on specific tiers.
   
   
2. Initial coverage phase — This is the phase after you have met your deductible (if it applies). Here, you’ll pay part of the cost (a copay or coinsurance) for your covered drugs. This phase ends when your total out-of-pocket costs for the year reach $2,100 (in 2026).
   
   
3. Catastrophic coverage phase — Once your out-of-pocket costs for covered drugs reach $2,100 (in 2026), you move to this phase. Here, you pay a $0 copay or coinsurance for your covered drugs through the end of the plan year.

Yes. Part D usually covers recommended adult vaccines to prevent illness.

Thanks to the Inflation Reduction Act, most Part D vaccines recommended for adults to prevent an illness now have a $0 copay. This includes the shingles vaccine. (Age limits may apply.)

Learn more about Medicare coverage for the shingles vaccine

 
Vaccines eligible for the $0 copay are those recommended by the CDC Advisory Committee on Immunization Practices (ACIP).

You can check your drug list (formulary) for a list of covered vaccines. And talk to your doctor about which ones are right for you.