Medicare drug coverage (Part D), explained

What Part D is

Original Medicare (Part A and Part B) generally does not pay for most pills you pick up at the pharmacy. Part D is the coverage that does. It also covers many recommended vaccines.

Medigap policies sold after 2005 do not include drug coverage. If you have Original Medicare plus a Supplement, you still need a separate Part D plan if you want Medicare drug coverage.

Two ways to get it

You generally should not have two Part D plans at the same time.

Check your drugs and pharmacy

Each plan has its own list of covered drugs. That list is called a formulary. A medicine you take today might be covered, limited, or not on the list.

• Bring your bottle list. Have someone check each prescription, dose, and your pharmacy against that year’s plan materials.
• Pharmacy matters. A preferred pharmacy often costs less than a standard one. Mail-order can be cheaper for a 90-day supply. Using a pharmacy outside the network can cost much more.
• Some drugs need extra steps. The plan may require prior authorization, a quantity limit, or trying a similar drug first. Ask your doctor’s office to help with the paperwork.

What you pay

Monthly premium

Every Part D plan has a premium. Amounts vary. People with higher incomes may pay an extra amount on top.

Deductible and copays

Some plans have a deductible you pay first. After that, you usually pay a copay or a percentage at the pharmacy. Generic drugs often cost less than brand-name drugs.

Yearly cap in 2026

Once you have paid $2,100 out of pocket for covered Part D drugs in 2026, you pay $0 for those covered drugs for the rest of the year. You still pay your premium.

Insulin and vaccines

Covered insulin has a monthly cap. Many recommended vaccines are covered with no copay when you use the plan the right way. Confirm the current rules at Medicare.gov.

Extra Help

If your income and resources are limited, Extra Help can lower Part D costs. It can also let you change plans outside the usual windows. Start at Medicare.gov or 1-800-MEDICARE.

If you go 63 or more days in a row without Part D or other creditable drug coverage after you are first eligible, you may owe a late enrollment penalty for as long as you have Part D. “Creditable” means coverage at least as good as Medicare’s. Ask before you skip a plan.

When you can join or switch

1. 1. When you first get Medicare

   You can join a drug plan during your Initial Enrollment Period. If you already have creditable drug coverage from a job, you may be able to wait.

2. 2. Each fall: October 15–December 7

   Open Enrollment. You can join, switch, or drop a Part D plan. Changes usually start January 1. This is also when you should compare next year’s drug list.

3. 3. Special situations

   Moving, losing other coverage, or qualifying for Extra Help or Medicaid can open a Special Enrollment Period. If you are in Medicare Advantage, the January 1–March 31 window can also change your drug coverage when you switch plans.

Drug lists, pharmacies, and prices can change every January. Read the Annual Notice of Change. Requesting a plan review with us does not enroll you.

Related: Medicare Advantage · Medicare Supplement