Medicare Part D (Prescription Drug Coverage)
Medicare has five main parts: A (Hospital Insurance), B (Medical Insurance), C (Medicare Advantage), D (Prescription Drug Coverage), and Medigap (Medicare Supplement Insurance). Beneficiaries who opt to enroll in Original Medicare (Parts A and B) may also choose to enroll in Medicare Part D in order to help lower the costs of their prescription drugs.
Keep reading to learn what Medicare Part D entails, why people choose it, and how to enroll.
What is Medicare Part D?
Medicare Part D is the part of Medicare that provides prescription drug coverage. It helps lower the costs of brand-name and generic medications, helping to protect beneficiaries from high prescription drug expenses throughout the year.
Original Medicare (which consists of Parts A and B, Hospital and Medical coverage) does not cover most outpatient prescriptions. Because of this, many people enroll in a standalone Part D Prescription Drug Plan (PDP) or choose a Medicare Advantage plan (Part C) that includes drug coverage (MAPD).
Similar to Medicare Advantage, standalone Medicare Part D plans are offered by private insurance companies that have been approved by Medicare; each plan comes with its own list of covered drugs, premiums, and pharmacy networks.
What does Medicare Part D cover?
There are many options for Medicare Part D plans; amongst them, they typically cover a wide range of prescription medications that beneficiaries typically need for chronic and acute health conditions.
💡 Something to Remember: Every Part D plan must meet Medicare's minimum coverage rules, but because Part D plans are offered by private insurance companies, each company has some flexibility in creating its drug list (called a formulary).
Here is a list of things that Medicare Part D plans do often cover:
Prescription Drugs: Part D formularies typically cover a wide range of outpatient prescription medications, including drugs for chronic conditions such as high blood pressure, diabetes, depression, high cholesterol, asthma, and more.
Brand-Name & Generic Drugs: Plans must cover both types, but your copays differ depending on the drug tier. Be sure to check the plan's formulary to confirm specific drug coverage.
Vaccines Recommended by ACIP: Starting in 2023, adult vaccines recommended by the Advisory Committee on Immunization Practices (including shingles (Shingrix) and Tdap) are covered at no additional cost under Part D.
Insulin: Under recent Medicare changes, injectable insulins may be covered, and are capped at $35 per month at participating pharmacies.
HIV/AIDS, Cancer & Antipsychotic Medications: Medicare requires all Part D plans to cover “protected classes” of medications that treat serious conditions.
Medication Management Services: If you take multiple prescriptions, you may qualify for Medication Therapy Management (MTM), which includes professional help reviewing your medications for safety and effectiveness.
What Does Medicare Part D Not Cover?
While many Part D plans offer comprehensive prescription drug coverage under the plan's formulary, there are some medications and services that fall outside of its coverage range. Here's what Part D doesn't cover:
Over-the-Counter (OTC) Drugs: Vitamins, supplements, cold medicine, and pain relievers are not included (unless prescribed under very specific circumstances).
Drugs Covered by Medicare Parts A or B: If a drug falls under inpatient (Part A) or outpatient medical services (Part B), Part D won't cover it. An example of this would be chemotherapy that is administered in a doctor's office.
Cosmetic Medications: Drugs for hair growth, wrinkle treatments, or cosmetic weight loss are not covered.
Fertility or Erectile Dysfunction Drugs: Part D excludes Viagra, Cialis (for ED), fertility medications, and similar drugs.
Experimental or Investigational Medications: Drugs not approved by the FDA are excluded from Medicare Part D coverage.
Medicare Part D Eligibility
The eligibility requirements for Medicare Part D are fairly simple; you are eligible for Medicare Part D if:
You are enrolled in Medicare Part A, Part B, or both.
You live within your chosen plan's service area.
Are a U.S. citizen or lawfully present in the U.S.
There are no medical underwriting requirements (this means you cannot be denied a Part D plan based on health conditions or the medications you take).
Medicare Part D Costs
Medicare Part D costs vary widely by plan and depend on medication coverage, pharmacy choice, location, and whether you qualify for financial assistance such as Extra Help.
While an estimate of costs cannot be provided without further information about your needs, you can use a Medicare plan comparison tool like Healthpilot to compare coverage options.
Your total costs for Medicare Part D coverage will depend on which plan you choose. Depending on the plan, you may be required to pay: the monthly premium, deductible, copayments and/or coinsurance. When budgeting for Medicare Part D, here's what to keep in mind:
Medicare Part D Premiums
As stated previously, your Medicare Part D monthly premium depends on the plan you choose. Some Medicare Advantage plans include Part D coverage (MAPD) at no additional premium, while standalone Part D plans have varied monthly premiums.
Medicare Part D Deductible
Most Medicare Part D plans have an annual deductible; the amount you must pay before your plan begins covering medications. Medicare sets a maximum deductible each year ($615 for 2026), but many plans offer lower deductibles or waive them for lower-tier drugs.
Medicare Part D Out-of-Pocket Costs
Medicare Part D out-of-pocket costs work a little differently than for other Medicare parts. There are three Part D coverage stages, each with its own associated out-of-pocket costs:
Deductible Stage: During this stage, the beneficiary pays 100% of drug costs until the plan's deductible is met.
Initial Coverage Stage: During this stage, after you reach your full deductible, you are responsible to pay copays or coinsurance; the plan pays the rest.
- This stage continues until your out-of-pocket spending on covered Part D drugs reaches $2,100 in 2026 (including certain payments made on your behalf, like through the Extra Help program). Then you will automatically get 'catastrophic coverage.'
Catastrophic Coverage: You won't have to pay out-of-pocket for covered Part D drugs for the rest of the calendar year.
| Coverage Stage | Definition |
|---|---|
| Deductible Stage | You are responsible for 100% of drug costs until your plan's deductible is met. |
| Initial Coverage Stage | You pay copays or coinsurance, and your Medicare Part D plan pays the rest. |
| Catastrophic Coverage | Once your out-of-pocket spending on covered Part D drugs reaches $2,100 in 2026, you won't have to pay out-of-pocket expenses for covered Part D drugs for the rest of the calendar year. |
How to Apply for Medicare Part D
You can enroll in a Part D plan when you first become eligible for Medicare or during specific Medicare enrollment periods.
Signing up is simple, and you can enroll:
Online
Over the phone
Through a licensed Medicare advisor
Directly through a Medicare Advantage plan that includes drug coverage
If you skip Part D when you first become eligible, and don't have other creditable drug coverage, you may owe a permanent late enrollment penalty that is added to your monthly premium. For this reason, it's important to sign up on time.
When to Enroll in Medicare Part D
You have the opportunity to enroll or add Medicare Part D coverage during several of Medicare's enrollment periods. You can enroll during:
Initial Enrollment Period (IEP) (your seven-month window): 3 months before, the month of, and 3 months after your 65th birthday (or Medicare disability eligibility). During this period, you can enroll in Original Medicare and choose to add a standalone Prescription Drug Plan.
Annual Enrollment Period (Open Enrollment) (mid-October to early December each year): During Open Enrollment, you can join, drop, or switch Part D plans for the upcoming year.
Special Enrollment Periods (SEPs): You may qualify for a Special Enrollment Period if you move, lose creditable coverage, or meet other conditions. An SEP will allow you to add a Prescription Drug Plan to your Medicare coverage.
How to Enroll in Medicare Part D
Enrolling in Medicare Part D is similar to enrolling in other parts of Medicare; most beneficiaries enroll through one of these methods:
Using an Online Tool Like Healthpilot: Healthpilot simplifies the process by comparing plans tailored to your medications, preferred pharmacies, and budget (plus, enrollment takes just minutes). Using Healthpilot, you can enroll:
Through a Medicare Advantage Plan: Choosing an MAPD (Medicare Advantage + Prescription Drug) plan combines medical and drug coverage.
Through a Standalone Part D Plan (PDP): This option works with Original Medicare or Medicare supplement insurance (Medigap).
Learn More About Medicare
Medicare Part D FAQs
Typically no; standalone Medicare Part D plans generally charge a monthly premium, deductibles, copayments and/or coinsurance.
Keep in mind that costs vary by plan, and some people may qualify for financial help through Extra Help, Medicaid, or states-specific pharmaceutical assistance programs.
A Medicare Part D plan is a prescription drug insurance plan offered by Medicare-approved private insurers. It helps cover the cost of outpatient prescription medications and is available either as a standalone plan (PDP) or bundled within a Medicare Advantage plan (MAPD).
Medicare Part D excludes coverage for some the following types of medications:
- Over the counter medications
- Erectile dysfunction meds
- Cosmetic drugs (e.g., hair growth treatments)
- Fertility medications
- Drugs paid for under Part A or Part B
- Experimental medications
Always check your plan's formulary to ensure your medications are covered.