Start with your actual prescriptions, not the plan name

The single most useful thing you can do before comparing Part D plans is to write down every prescription you take right now — the drug name, the dose, and how often you fill it. Not the brand name if there is a generic version; the actual drug name your pharmacy uses. This list is what you will use to check each plan's formulary, which is the list of drugs that plan covers.

Medicare's official tool, called Medicare Plan Finder, lets you enter your prescriptions and see which plans cover them and at what cost. You can reach it at Medicare.gov. The tool shows you not just whether a plan covers your drug, but what tier it is on (tier 1 is cheapest, tier 5 is most expensive) and what you will pay out of pocket. This is more useful than any plan summary, because it shows you the actual dollars you will spend.

If you do not have internet access or need help using the tool, you can call 1-800-MEDICARE and ask for a counselor to walk you through it. Many Area Agencies on Aging also offer free help with this step in person.

Key Takeaways

  • Enter your current prescriptions into Medicare Plan Finder before comparing plans, because the cost difference between plans for the same drug can be hundreds of dollars per year.
  • Part D plans change their formularies and costs every January, so you must check your plan's coverage each year during open enrollment, even if you have been happy with it.
  • The lowest monthly premium does not mean the lowest total cost — a plan with a higher premium might cover your drugs at a lower tier and cost you less overall.
  • If your plan stops covering a drug you need, you can switch plans outside the normal enrollment window, which is called a may have access to life event.
  • Generic drugs are almost always cheaper than brand-name versions on Part D plans, and your pharmacist can tell you if a generic is available for any of your medications.

Understanding the four costs you will pay

Every Part D plan has four separate costs, and understanding each one helps you predict what you will actually spend. The first is the monthly premium, which you pay whether you fill any prescriptions or not. The second is the annual deductible, which is the amount you pay out of pocket before the plan starts to help pay for drugs. Not all plans have a deductible, and some have a low one.

The third cost is coinsurance or copay, which is what you pay for each prescription after you have met the deductible. This is where the tier system matters: a tier 1 drug might cost you $5 per fill, while a tier 3 drug costs $45. The fourth cost is the coverage gap, also called the donut hole. Once you and your plan have spent a certain amount on drugs in a calendar year (the threshold changes yearly), you enter the gap and pay a higher percentage of the drug cost until you reach catastrophic coverage.

Medicare Plan Finder will show you all four costs for each plan, calculated based on your specific prescriptions. This is the number to use when you compare plans, not the premium alone.

How to use Medicare Plan Finder step by step

Go to Medicare.gov and look for the Plan Finder tool. You will need your Medicare number, which is on your Medicare card. You will also need to enter your zip code, because Part D plans are regional and what is available in one county may not be available in another.

When the tool asks for your prescriptions, enter them one by one. Use the exact drug name (for example, "metformin" not "diabetes medicine"), the dose, and how often you fill it. If you are not sure of the exact name, call your pharmacy and ask them to read it from the label. Once you have entered all your drugs, the tool will show you a list of plans ranked by estimated yearly cost.

Click on each plan to see the full details: the monthly premium, the deductible, the copays for each of your drugs, and whether there are any restrictions like prior authorization (where the plan makes you get permission before filling a drug). Read the formulary document for any plan you are seriously considering, because the summary can miss details.

When a plan does not cover the drug you need

If your current plan stops covering a drug, or if you are choosing a plan for the first time and none of the plans cover a drug you take, you have options. The first is to ask your doctor whether a different drug in the same class would work for you — for example, if your plan does not cover one blood pressure medication, it may cover another. Your doctor can often switch you with a straightforward phone call to your pharmacy.

The second option is to ask the plan for an exception. This is a formal request to cover a drug that is not on the formulary. The plan will ask your doctor to explain why this specific drug is medically necessary for you. Some plans grant exceptions; some do not. The process usually takes a few days to a week.

The third option is to switch to a different Part D plan. If your current plan stops covering a drug you have been taking, you can change plans outside the normal open enrollment window — this is called a may have access to life event. You have 60 days from the date the plan notifies you of the coverage change to switch to a new plan.

Comparing plans when you take many drugs or expensive ones

If you take multiple medications or any drug that is expensive, the coverage gap becomes important. Once your total drug costs reach a certain amount (the threshold is set by Medicare each year), you enter the gap and pay more out of pocket. Some plans have better gap coverage than others, and some drugs are covered differently in the gap than they are before it.

When you use Medicare Plan Finder, it will show you your estimated costs through the entire year, including the gap. This is the most accurate way to compare plans if you take expensive drugs. Do not just look at the premium and the copay for one drug; look at the total yearly cost across all your prescriptions.

If you reach catastrophic coverage (which happens after you have spent a certain amount out of pocket), your costs drop significantly. The plan then covers most of the cost of your drugs for the rest of the year. This matters most if you take very expensive medications or have multiple chronic conditions.

Open enrollment and when you can change plans

Part D plans change their formularies, costs, and coverage every January 1st. This means a plan that was perfect for you last year might cover your drugs differently this year, or the copay might go up. You have one chance per year to change plans without penalty, during the annual open enrollment period from October 15th to December 7th. Any plan change you make during this window takes effect on January 1st.

If you miss open enrollment and do not change plans, you are locked into your current plan for the rest of the year. The only exception is if you have a may have access to life event, such as a plan stopping coverage of a drug you need, moving to a new state, or losing other insurance. When a may have access to event happens, you have 60 days to switch plans.

Mark your calendar for mid-October each year to review your plan. Even if you have been happy with it, spend 15 minutes checking whether your drugs are still covered and whether the costs have changed. This one task can save you hundreds of dollars.

Generic drugs and how they affect your costs

Generic drugs are chemically identical to brand-name drugs and work the same way in your body. On Part D plans, they are almost always on a lower tier, which means you pay less for them. If you take a brand-name drug and a generic version exists, switching to the generic will lower your out-of-pocket cost.

Some people worry that generics are not as good as brand-name drugs, but this is not true. The FDA requires generics to be as safe and effective as the brand-name version. Your pharmacist can tell you whether a generic is available for any of your medications. If your doctor prescribed a brand-name drug specifically because the generic does not work for you, tell your pharmacist — they can note this in your file so the pharmacy does not automatically substitute the generic.

When you compare plans using Medicare Plan Finder, the tool assumes you will use the generic version if one is available. If you are determined to use a brand-name drug instead, your costs will be higher, and you should ask the plan about this before you enroll.

Frequently Asked Questions

Can I change Part D plans in the middle of the year?

Only if you have a may have access to life event, such as your plan stopping coverage of a drug you need, moving to a different state, or losing other insurance. When this happens, you have 60 days to switch. Otherwise, you can only change plans during open enrollment in October and November.

What if I cannot afford the copay for a drug I need?

Ask your pharmacy about patient information programs run by the drug manufacturer, which often provide drugs free or at low cost to people who cannot afford them. You can also ask your doctor about switching to a cheaper drug in the same class. Some Part D plans also have programs to help people with high costs; call the plan to ask.

Do I have to pick a plan every year, or does it stay the same?

Your plan stays the same unless you change it. But you should review your plan every October, because the formulary and costs change on January 1st. If your plan no longer covers your drugs or the costs went up, you can switch during open enrollment.

What is the difference between a standalone Part D plan and Part D through a Medicare Advantage plan?

A standalone Part D plan works with Original Medicare (Parts A and B). A Medicare Advantage plan includes drug coverage built in. If you have Medicare Advantage, you cannot also buy a standalone Part D plan. Use Medicare Plan Finder to compare the drug coverage in your Medicare Advantage plan against standalone options to see which is cheaper for your prescriptions.

Can I see my doctor's preferred pharmacy on the plan's website?

Yes. Every Part D plan has a network of pharmacies where your copay is lowest. Before you enroll, check whether your current pharmacy is in the network. If it is not, you can either switch pharmacies or ask the plan whether they will cover your prescriptions at your current pharmacy at a higher cost.