Medicare Part D: Your Prescription Drug Coverage Choices

Medicare Part D is optional prescription drug coverage provided by private insurance companies that work with Medicare. You can get it either as a stand-alone plan to add to Original Medicare, or it may be included in a Medicare Advantage plan.

Key Takeaways

• Medicare Part D provides prescription drug coverage through private insurance plans.
• Part D plans have formularies, which are lists of covered drugs organized into cost tiers.
• Costs include premiums, deductibles, copays, or coinsurance, with a yearly out-of-pocket cap of $2,100 in 2026.
• The Medicare Prescription Payment Plan helps spread high drug costs throughout the year for those who enroll.
• Using the Medicare Plan Finder tool on Medicare.gov is a valuable resource for comparing plans based on your specific medications.

What is Medicare Part D?

Medicare Part D is optional prescription drug coverage. It helps you pay for your prescription medications. Private insurance companies, approved by Medicare, offer these plans.

These plans work with Medicare. They follow specific rules set by the Centers for Medicare & Medicaid Services (CMS). CMS sets federal standards for coverage that all plans must meet, ensuring a baseline of benefits.

However, each private plan can decide its own list of covered drugs. This key list is called a formulary. Plans also set their own specific costs for drugs and services, so these can vary greatly.

You can get Part D in two main ways. One is a stand-alone plan if you have Original Medicare (Part A and Part B). The other is as part of a Medicare Advantage (Part C) plan, offering an all-in-one approach.

How Part D Works with Other Medicare Parts

Original Medicare, which includes Part A and Part B, generally does not cover outpatient prescription drugs. Part A helps with hospital stays and skilled nursing facility care. Part B covers doctor visits, medical supplies, and outpatient services.

Since Original Medicare does not cover most prescriptions you pick up at a pharmacy, Part D helps fill this coverage gap. If you have Original Medicare, you choose to add a stand-alone Part D plan. This helps you have coverage for your medications.

Many Medicare Advantage plans (Part C) include drug coverage. These are called Medicare Advantage Prescription Drug (MA-PD) plans. With an MA-PD plan, you get your medical and drug benefits all together in one comprehensive plan.

Medicare Part B does cover some specific drugs. These are usually given to you in a doctor's office or hospital outpatient setting, not self-administered. Examples include certain injected medications, infusions, or some chemotherapy drugs administered by a medical professional.

This means most prescriptions you fill at a local pharmacy are covered by Part D. Part B rarely covers these everyday medications. Understanding these differences helps you avoid unexpected costs and ensures you choose the correct coverage.

It is helpful to understand the differences in how you get drug coverage. Your health needs and personal preferences will guide your choice. Both options provide valuable prescription drug benefits, but they structure your overall Medicare coverage differently.

What Drugs Does Part D Cover?

Each Part D plan has a list of covered drugs. This list is called a formulary. A plan's formulary must include a wide variety of medications to meet federal requirements.

Federal rules state that formularies must cover at least two drugs in each drug class. They also must include most common vaccines. This offers a broad range of choices for beneficiaries, but specific brand names may vary.

Formularies organize drugs into different tiers. Each tier has a specific cost level that you will pay. You will typically pay less for drugs in lower tiers. The number and types of tiers can vary by plan, usually from three to five.

• Tier 1: Preferred Generic Drugs: These usually have the lowest copayments. You might pay $0 to $5 for these medications. They are often the most cost-effective choice and widely available.
• Tier 2: Non-Preferred Generic Drugs: These have slightly higher copayments than preferred generics. They are still usually affordable and a common option for many conditions.
• Tier 3: Preferred Brand-Name Drugs: These drugs have moderate copayments or coinsurance. They are often common brand-name medications that are widely used and have a good track record.

• Tier 4: Non-Preferred Brand-Name Drugs: These have higher coinsurance. Your cost might be 25% to 40% of the drug's total cost. These are typically more expensive options, often newer or specialized drugs.
• Tier 5: Specialty Drugs: These are often very high-cost drugs. They usually have the highest coinsurance or fixed dollar copays. These medications treat complex or rare conditions and may require special handling.

Plans can change their formulary each year. A drug covered one year might move to a higher tier next year. It could also be removed entirely from the plan's coverage list if alternatives become available or cheaper.

Plans must notify you about these important changes. You receive an Annual Notice of Change (ANOC) each fall, typically in September. Reviewing this notice carefully is important to understand your upcoming year's coverage and make any necessary plan changes during Open Enrollment.

If a drug you need is not on your plan's formulary, you generally pay its full cost out-of-pocket. However, you can ask your plan for an exception. This is called a formulary exception request, and it allows you to request coverage for a non-formulary drug.

Your doctor must provide a medical reason for this request. They must explain why you need that specific drug and why other covered alternatives will not work. This process helps you get necessary medications, even if they aren't on the standard list, subject to plan approval.

What Are Part D Costs?

Understanding Part D costs involves several parts that make up your total expense. These costs can vary greatly by plan. They also depend on the specific drugs you take and their tier placement.

Monthly Premium: This is a fee you pay each month directly to your plan. Premiums vary widely among different plans. Some plans have lower premiums but higher costs when you fill prescriptions, while others might have higher premiums but lower out-of-pocket costs at the pharmacy for your drugs.

Annual Deductible: This is the amount you pay for your prescriptions yourself. You must meet this amount before your plan starts to pay its share. The maximum Part D deductible in 2026 is $615, meaning plans cannot charge more than this.

Some plans offer a lower deductible than the maximum. Many plans even have a $0 deductible for certain tiers of drugs, typically generics. This means coverage for those specific drugs starts right away, without you needing to meet a deductible first.

Copayments and Coinsurance: After you meet your deductible, you pay a share of the drug cost. A copayment is a fixed amount, such as $10 for a generic drug. This amount does not change based on the drug's total cost, offering predictability.

Coinsurance is a percentage of the drug's cost. For example, you might pay 25% for a brand-name drug. Both of these contribute to your total out-of-pocket spending for the year, and plans vary on which they use for different tiers.

Out-of-Pocket Cap: In 2026, once your out-of-pocket spending on covered drugs reaches $2,100, your plan pays 100% of costs. This covers all covered drugs for the rest of the calendar year. This cap provides significant financial protection against high drug costs. Learn more at Understanding Your Part D $2,100 Drug Cap and the Eliminated Donut Hole.

Income-Related Monthly Adjustment Amount (IRMAA): If your income is above a certain level, you will pay an extra amount for Part D. This extra amount is added directly to your Part D premium. It is officially called the Part D IRMAA.

Medicare determines your IRMAA based on your income from two years prior. For example, your 2026 IRMAA is based on your 2024 income. This adjustment means that those with higher incomes contribute more to their Part D costs, as required by law.

The Medicare Prescription Payment Plan

All Medicare drug plans must offer the Medicare Prescription Payment Plan. This plan helps manage high prescription drug costs. It spreads them out over the remaining months of the calendar year.

If you opt into this plan, you will pay $0 at the pharmacy counter. This applies to your covered Part D drugs. Instead, your out-of-pocket drug costs are spread into manageable monthly payments for the rest of the year.

These monthly payments cover your remaining costs for the calendar year. This plan does not lower your total drug costs. It only changes when you pay them, offering cash flow relief by avoiding large upfront payments.

This can be beneficial if you anticipate high costs early in the year, such as for a new specialty medication. A pharmacy or plan may tell you about this plan if one prescription would cost $600 or more out of pocket for you. For more detailed information, see Managing High Drug Costs: The Medicare Prescription Payment Plan.

Avoiding the Part D Late Enrollment Penalty

It is beneficial to enroll in a Part D plan when you are first eligible. If you go without creditable prescription drug coverage for 63 or more days in a row, you may face a permanent penalty.

Creditable drug coverage means coverage that is at least as good as Medicare's Part D. This includes most employer or union drug coverage, as well as TRICARE or VA benefits. Your plan provider should tell you each year if your coverage is creditable. For details on avoiding penalties, see Medicare Part D: Avoiding Late Enrollment Penalties.

This penalty can apply after your Initial Enrollment Period ends. The Part D late enrollment penalty is permanent. It is added to your monthly Part D premium for as long as you have any Medicare drug coverage.

The penalty is calculated as 1% of the national base beneficiary premium. This is for each full month you went without creditable coverage when you could have had Part D. The 2026 national base beneficiary premium is $38.99.

For example, if you had 14 months without creditable coverage, your penalty calculation begins. Your penalty would be 14% (1% for each month) of the $38.99 national base beneficiary premium, which is $5.46. This amount is then rounded to the nearest $0.10, making it $5.50 a month.

This $5.50 amount is added to your monthly Part D premium for 2026. This penalty amount is recalculated yearly based on the new base premium, so it can change each year. Even with few prescriptions, enrolling early can help you avoid this permanent penalty. People who qualify for Extra Help (Low-Income Subsidy) do not pay this Part D late enrollment penalty.

Comparing Part D Plans: What to Look For

Choosing a suitable Part D plan is a very personal decision. Taking the time to compare plans can also help you manage your costs effectively. Do not just pick a plan based on the lowest monthly premium alone; a thorough review is key.

A plan with a low premium might have higher costs for your specific drugs, or a higher deductible. Comparing plans based on your actual medication needs can help you find value and potentially lower your out-of-pocket expenses for the entire year.

The Medicare Plan Finder tool on Medicare.gov is a valuable, free online resource. It provides personalized comparisons based on your specific medications and preferred pharmacies. Using this tool can make your plan search much easier and more accurate.

Here are some steps to help you compare plans effectively and find one that works well for you:

• Make a list of all your medications. Include the exact drug names, their dosages, and how often you take them. This is a key step for accurate comparisons, ensuring no medication is overlooked.

• Enter your drugs into the Medicare Plan Finder tool. This tool will show estimated costs for all plans in your area. This includes premiums, deductibles, and drug costs for your specific medications throughout the year.
• Check if your preferred pharmacy is in the plan's network. Many plans have preferred pharmacies, which offer lower copayments. Using an in-network pharmacy can often lower your copayments, so check for available options near you.

• Consider mail-order options. Some plans offer lower costs or larger supplies (like a 90-day supply) if you use their preferred mail-order pharmacies. This can be convenient for maintenance medications and may save you money.
• Review the formulary and tier placement for your drugs. Make sure your important drugs are covered. See which tier they fall into, as lower tiers mean lower costs for you.
• Consider the plan's deductible. Some plans have a $0 deductible, meaning coverage starts right away. Others have the maximum $615 deductible in 2026, which you must meet before the plan begins to pay its share.

It is a good idea to compare plans every year. Do this during the Annual Open Enrollment Period (October 15 – December 7). Plan formularies and costs can change each year, so what was suitable one year may not be the next.

An annual review can help you determine if you still have a suitable plan for your needs and budget. Your health and medications might also change, making a yearly check-up on your plan a smart financial and health decision.

Extra Help (Low-Income Subsidy) for Drug Costs

Medicare offers a program called Extra Help, also known as the Low-Income Subsidy (LIS). This program assists people with limited income and resources. It helps pay for many of your Part D costs.

If you qualify for Extra Help, it can help reduce your drug expenses. It helps with monthly premiums, yearly deductibles, and copayments. This makes your necessary medications more affordable and accessible.

To qualify for Extra Help in 2026, your income must be below $23,475 a year if you are single. For a married couple living together, your income must be below $31,725. These limits can change annually, so check current figures on Medicare.gov.

Your resources must be below $18,090 if you are single. For a married couple, resources must be below $36,100. Some income and resources, such as the value of your home, do not count toward these limits, which can be helpful.

If you qualify, your copays for drugs will be lower. In 2026, they will be at most $5.10 for a generic drug. They will be at most $12.65 for a brand-name drug, which can offer a valuable saving. Some people with full Medicaid benefits may pay even less. You can apply for Extra Help through the Social Security Administration (SSA). You can visit SSA.gov or call them directly for more information. This program provides valuable support. It helps people access needed prescription drugs and can reduce the financial burden for many beneficiaries.

Your Part D Enrollment Periods

Knowing when you can sign up or change your Part D plan is a key step for your coverage. Missing these specific periods can lead to penalties and can also cause gaps in your coverage.

Initial Enrollment Period (IEP): This is your first chance to enroll in Medicare, including Part D. It is a seven-month period. It includes the three months before your 65th birthday month.

It also includes your birthday month itself. Finally, it covers the three months after your birthday month. You should try to enroll in Part D during this time to help avoid potential penalties and ensure continuous coverage.

Enrolling during your IEP helps you avoid late enrollment penalties. Your drug coverage can start when your other Medicare benefits begin. This can provide continuous coverage for your medications from the start, preventing any gaps.

Annual Open Enrollment Period: This key period runs from October 15 to December 7 each year. During this time, you can make several changes to your Medicare coverage. These changes become effective on January 1 of the next year.

You can join a Part D plan for the first time. You can also switch from one Part D plan to another that better suits your needs. Or, you can choose to drop your Part D coverage entirely, though this may lead to penalties later if you don't have other creditable coverage.

This period also allows you to switch between Original Medicare and a Medicare Advantage plan. You can change your Medicare Advantage plan too. Reviewing your options yearly is important as your needs and plan offerings may change.

Medicare Advantage Open Enrollment Period: This period runs from January 1 to March 31 each year. If you are already in a Medicare Advantage plan, you can make a one-time change during this window.

You can switch to a different Medicare Advantage plan that might offer better benefits or lower costs. You can also switch from a Medicare Advantage plan to Original Medicare. If you switch to Original Medicare, you can then join a stand-alone Part D plan to cover your prescriptions.

Special Enrollment Periods (SEPs): These periods allow you to make changes outside of normal enrollment times. They are for specific life situations and are not available to everyone. Examples include moving to a new area that your current plan does not serve, or losing other creditable drug coverage.

If you lose other creditable drug coverage, you might qualify for an SEP to join a Part D plan. People with Extra Help or Medicaid also have a monthly SEP. This lets them change Part D plans or switch from a Medicare Advantage plan to Original Medicare plus a stand-alone Part D plan, once per calendar month.

Carefully choosing your Part D plan is an important step in managing your health and finances. Review your options yearly to help ensure your plan continues to meet your prescription drug needs and budget effectively, as plans and your health can change.

Have questions? Call 1-877-443-3251 to talk it through with a licensed insurance agent. They're paid by the plans they represent, never by you, and the decision stays yours.

We do not offer every plan available in your area. Any information we provide is limited to those plans we do offer in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options. Medicare has neither reviewed nor endorsed this information.