Eligibility
Medicare enrollment comes first
To join a standalone Part D plan, you generally need Medicare Part A or Part B, must live in the plan service area, and must meet Medicare citizenship or lawful residence requirements.
Prescription drug coverage
Medicare Part D, explained simply.
Part D helps pay for covered prescription drugs. Start with the basics, then compare plans around the medications and pharmacies you use.
Start with the basics
Two ways to get Medicare drug coverage
You can add drug coverage to Original Medicare or choose a Medicare Advantage plan that includes it.
A standalone Part D plan works alongside Original Medicare. It is offered by a private insurance company approved by Medicare and has its own covered drug list, pharmacy network, and costs.
Many Medicare Advantage plans include Part D coverage within the same plan. In most Medicare Advantage plan types, you cannot add a separate Part D plan. Certain PFFS plans without drug coverage and MSA plans may allow a standalone Part D plan.
Covered medications
How formularies and drug tiers work
Every Part D plan has a formulary, which is the plan's list of covered prescription drugs.
Part D plans cover brand name and generic drugs. Plans must cover most drugs in six protected classes: cancer drugs, HIV/AIDS drugs, antidepressants, antipsychotics, anticonvulsants, and immunosuppressants used after an organ transplant.
Plans place covered medications into tiers. Your cost may depend on the tier, whether the drug is brand name or generic, and the pharmacy you use.
A plan may use rules such as prior authorization, quantity limits, or step therapy. If a medication is not covered as expected, you or your prescriber may be able to request an exception.
- Confirm that every prescription is on the formulary
- Review the tier and estimated cost for each medication
- Check for restrictions or approval requirements
- Review the formulary again when plan details change
Understanding costs
How your Part D costs can change during the year
Your total cost depends on your plan, prescriptions, pharmacy, and how much you spend on covered drugs.
- 1
Monthly premium
Most plans charge a monthly premium. Your income may also affect what you pay.
- 2
Plan deductible
Some plans require you to pay a deductible before the plan begins sharing certain drug costs.
- 3
Copays or coinsurance
Your share can vary by drug tier and by the pharmacy or delivery option you choose.
- 4
Yearly out of pocket limit
After your out of pocket spending on covered Part D drugs reaches the annual limit, you pay nothing for covered Part D drugs for the rest of the calendar year. The limit can change each year.
Before you enroll
Know your timing and eligibility
Your Medicare status, current drug coverage, and life changes can affect when you may enroll.
Timing
Use the enrollment period available to you
Your first chance generally aligns with your Medicare Initial Enrollment Period. You can also join or change coverage during Open Enrollment from October 15 through December 7, or during a Special Enrollment Period if you qualify.
Late enrollment
Avoid an uncovered gap
A penalty may apply if, after you become eligible, you go 63 days or more in a row without Part D or other creditable drug coverage. Keep proof of creditable coverage and review your plan each fall.
Compare what matters
Choose a plan around your prescriptions
A low premium does not always mean the lowest total cost. Review the full picture before enrolling.
Medications
Your complete prescription list
Check every medication, dose, and refill frequency against the plan formulary.
Pharmacy
Where you fill prescriptions
Confirm that your pharmacy is in the plan network and whether another network pharmacy offers preferred pricing.
Coverage rules
Tiers and restrictions
Review drug tiers, prior authorization, quantity limits, and step therapy requirements.
Total cost
What you may pay across the year
Consider premiums, deductibles, copays, coinsurance, and expected prescription use together.
Convenience
Retail or mail order
Check whether the plan offers a mail order option and compare its cost and delivery terms with local pharmacies.
Choosing and using coverage
From comparing plans to your first refill
A clear process can help you choose and start using coverage with fewer surprises.
- 1
Compare plans in your area
Enter your ZIP code, then compare formularies, pharmacies, premiums, deductibles, and expected drug costs using your current prescription list.
- 2
Submit your enrollment
Once you choose a plan, enroll through an approved enrollment source or contact the plan. Keep the confirmation number and effective date.
- 3
Review your membership materials
Confirm your covered drugs, pharmacy network, coverage rules, and membership card when the plan materials arrive.
- 4
Fill your prescriptions
Bring your plan membership card and a photo ID. If the card has not arrived, ask which confirmation document or digital card the pharmacy can accept.
Could you qualify for help with prescription costs?
Medicare Extra Help may lower premiums, deductibles, and copays for people with limited income and resources. Eligibility is determined by the appropriate government program.
Call (877) 255-6273TTY: 711
Part D questions
Clear answers about prescription coverage
Start with the questions people ask most often when choosing and using Part D.
Choosing coverage
Using coverage
Changes and claims
Personalized guidance
Talk through your prescription coverage
Share your questions and a licensed sales agent can help you understand the Part D options available in your area.