What to Look for When Comparing Part D Plans

Medicare Part D plans differ in which drugs they cover, what you pay at the pharmacy, and which pharmacies you can use. Before you compare, gather three pieces of information: the list of medications you take (including the dose and how often), the pharmacies where you fill prescriptions, and how much you can spend out of pocket each month. With those details, you can use the Medicare Plan Finder tool on Medicare.gov to see actual costs for your specific situation — not just general plan features.

Every Part D plan has a formulary, which is the official list of drugs the plan covers. Plans are not required to cover every medication, and some drugs require approval from the plan before the pharmacy will fill them. If a drug you take is not on a plan's formulary, you will pay the full pharmacy price unless you request an exception from the plan. The Plan Finder shows you which of your medications are covered and at what cost tier.

Cost tiers determine what you pay. Tier 1 drugs (usually generics) cost the least. Tier 2 (preferred brand-name drugs) cost more. Tier 3, 4, and 5 cost progressively more, and some plans charge a percentage of the drug's price rather than a flat amount. A plan that looks cheap at first glance might be expensive for you if most of your medications land on higher tiers.

Key Takeaways

  • Use the Medicare Plan Finder tool with your actual medications to compare real out-of-pocket costs, not just plan names or monthly premiums.
  • Check whether your pharmacy is in the plan's network and whether your medications are on the plan's formulary before you choose.
  • Plans with lower premiums sometimes have higher costs at the pharmacy, so compare your total yearly spending across the whole plan, not just the monthly fee.
  • You can change Part D plans once a year during the Annual Enrollment Period (October 15 to December 7), or if a major life event occurs, you may have a Special Enrollment Period.
  • If your plan stops covering a drug you need or raises the price too high, you can request an exception or switch plans outside the normal enrollment window.

Using the Medicare Plan Finder Tool

Go to Medicare.gov and select "Find Care Providers and Suppliers" or search directly for "Plan Finder." You will enter your medications (search by name or by condition), your pharmacy, and your zip code. The tool shows you every Part D plan available in your area, ranked by estimated yearly cost for your specific drugs. This is the most accurate way to compare because it accounts for your actual prescriptions, not hypothetical ones.

The Plan Finder displays your estimated costs in several ways. "Your estimated yearly drug costs" shows what you would pay out of pocket across the whole year under that plan. "Monthly premium" is what you pay to the plan whether you fill prescriptions or not. "Pharmacy cost" shows what you pay when you pick up each drug. Read all three numbers before deciding — a plan with a $0 premium might cost you $3,000 a year in pharmacy costs, while a plan with a $35 monthly premium might cost you $1,500 a year total.

The Plan Finder also shows whether each pharmacy you use is in the plan's network. Out-of-network pharmacies usually cost more or are not covered at all. If you have a pharmacy you prefer, check that it is in the plan before you choose. Some plans have mail-order options or partnerships with specific chains, so confirm the details match your routine.

Understanding the Coverage Gap and Catastrophic Coverage

Part D has a structure called the coverage gap, sometimes called the "donut hole." After you and your plan have spent a certain amount on covered drugs (the initial coverage limit, which changes yearly), you enter the gap and pay a higher percentage of drug costs. Once your out-of-pocket spending reaches a second threshold (the out-of-pocket maximum), catastrophic coverage begins and you pay a small copay or coinsurance for the rest of the year.

The Plan Finder estimates whether you will hit the gap based on your medications. If you take many expensive drugs, you might reach catastrophic coverage, where costs drop again. If you take a few inexpensive drugs, you may never leave initial coverage. Understanding where you fall helps you predict your yearly costs and compare plans fairly. Some people benefit from plans with higher premiums if those plans have better coverage in the gap.

Checking Your Pharmacy and Getting Prior Authorization

Before you choose a plan, call or visit your pharmacy to confirm it is in the network. Some independent pharmacies or specialty pharmacies are not in every plan's network. If your pharmacy is not in a plan you like, ask whether the plan has other locations nearby or whether you can transfer prescriptions to a network pharmacy.

Some drugs require prior authorization, meaning the plan must approve them before the pharmacy will fill the prescription. The Plan Finder notes which of your drugs need authorization. If a drug requires it, the process usually takes a few days, so plan ahead if you are running low. You or your doctor can request the authorization — the plan will contact your doctor for medical information if needed.

If a drug you need is not on the formulary, you can ask your doctor to request an exception. The plan will review whether the drug is medically necessary and whether a formulary drug would work instead. Exceptions are sometimes granted, but they take time, so do not wait until you are out of medication to request one.

When You Can Switch Plans

The Annual Enrollment Period runs from October 15 to December 7 each year. During this time, you can switch to a different Part D plan, and your new coverage starts January 1. This is the main window for changes. If you miss this important date, you are locked into your current plan until the next October.

A Special Enrollment Period lets you change plans outside the normal window if you have a may have access to event: you lose your current coverage, you move out of the plan's service area, your plan stops covering a medication you need, or you experience other major changes. You must request the change within 60 days of the event. Contact Medicare at 1-800-MEDICARE to find out whether your situation qualifies.

If your plan raises prices or stops covering a drug mid-year, you do not have to wait until October. Document the change (a letter from your plan or a pharmacy receipt showing the new cost) and call Medicare to ask about your options. Some situations do may have access to for a Special Enrollment Period even if they seem minor.

Comparing Costs Beyond the Monthly Premium

A plan's monthly premium is only one piece of the cost picture. Two plans might have very different premiums but similar total yearly costs if one has higher pharmacy copays. Use the Plan Finder's "estimated yearly drug costs" number to compare apples to apples.

Some plans offer $0 premiums but charge $50 or more per prescription. Others charge $40 a month but only $10 per drug. If you fill many prescriptions, the higher-premium plan might save you money. If you fill very few, the $0-premium plan might be better. The Plan Finder does this math for you based on your actual medications.

Also consider whether the plan covers brand-name drugs or pushes you toward generics. If your doctor says a generic will not work for you, a plan that covers the brand-name drug at a reasonable cost might be worth a higher premium. Conversely, if generics work fine, a plan with strong generic coverage and weak brand-name coverage could save you money.

What to Ask Your Doctor and Pharmacist

Before you choose a plan, ask your doctor whether any of your medications have generic versions that work as well as the brand name. Ask whether any drugs require prior authorization or have restrictions. If your doctor prescribed a brand-name drug, ask whether a generic would be appropriate — this can lower your costs significantly under most plans.

Ask your pharmacist which of your medications are available as generics and what the price difference is. Ask whether your pharmacy is in the networks of the plans you are considering. If your pharmacy is not in a plan's network, ask whether a nearby location is, or whether you can use mail order. Your pharmacist can also tell you whether any of your drugs have coverage restrictions or require prior authorization under typical plans.

Frequently Asked Questions

What if I take a drug that is not on any plan's formulary in my area?

Contact the plans that do cover the drug and ask about the cost. If none cover it, you can request an exception from a plan you choose, or ask your doctor whether an alternative drug on the formulary would work. If your doctor says the uncovered drug is medically necessary, some plans will cover it as an exception, though approval is not may provide.

Can I switch Part D plans if my plan raises the price of a drug I need?

Yes, if the price increase is significant enough to may have access to as a major change. Contact Medicare at 1-800-MEDICARE with proof of the price increase (a letter from your plan or a pharmacy receipt). Medicare will tell you whether you can switch outside the normal enrollment period. Even if you cannot switch when ready, you can switch during the next Annual Enrollment Period in October.

Do all Part D plans cover mail-order prescriptions?

Most plans offer mail-order options for maintenance medications (drugs you take regularly for chronic conditions), but not all cover mail order for short-term prescriptions. Check the plan's details in the Plan Finder or call the plan directly to confirm. Mail order is often cheaper than the pharmacy but takes longer, so plan ahead.

What happens if I choose a plan and then realize it does not cover one of my drugs?

You have a 14-day window after your coverage starts to change your mind and switch to a different plan. After that, you are locked in until the next Annual Enrollment Period unless you may have access to for a Special Enrollment Period. This is why using the Plan Finder with your actual medications before you choose is so important.

How do I know if my pharmacy is in a plan's network?

The Plan Finder shows you whether your pharmacy is in the network when you enter your zip code and pharmacy name. You can also call the plan directly or visit the plan's website and search for pharmacies by location. If your pharmacy is not in the network, ask whether the plan has other locations nearby or whether you can use mail order instead.