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Medicare 101

Understanding Medicare Prescription Drug Plans

Christian Worstell

by Christian Worstell | Published October 25, 2023 | Reviewed by John Krahnert

Original Medicare (Medicare Part A and Part B) and Medicare Supplement Insurance plans do not provide coverage for prescription drugs.

Medicare Part A and Part B beneficiaries who need prescription drug coverage may enroll in Medicare Part D Prescription Drug Plan.

If you do not enroll in a Medicare Part D plan when you’re first eligible, you may have to pay a late enrollment penalty. Therefore, it is important to familiarize yourself with your options early and enroll as soon as you’re eligible.

You can compare Part D plans available where you live and enroll in a Medicare prescription drug plan online when you visit

Enroll in Medicare Part D at


Who’s eligible for a Medicare Prescription Drug Plan?

You’re eligible for Medicare Part D if:

  • You’re enrolled in Original Medicare

  • You live in a service area of a Medicare Part D Prescription Drug Plan

Note: You are not eligible for Medicare Part D if you’re currently enrolled in a Medicare Advantage (Medicare Part C) plan that provides prescription drug coverage. If you’re enrolled in a Medicare Advantage plan that does not provide prescription drug coverage, you may enroll in Medicare Part D.

When can I enroll?

If you need coverage for prescription drugs, we recommend enrolling in a Medicare Prescription Drug Plan when you’re first eligible.

If you’re 65 years or older

You’re first eligible to sign up for Medicare Part D coverage during your Medicare Initial Enrollment Period, which begins three months before your 65th birthday and ends three months after you turn 65.

If you’re younger than 65

If you are younger than 65 and are eligible for Medicare due to a qualifying disability or medical condition, you can enroll in a Medicare Part D plan when you first become eligible for Medicare.

  • If you receive disability benefits from Social Security or the Railroad Retirement Board, you will be automatically enrolled in Original Medicare on the 25th month of receiving your disability benefits.

  • If you have ALS or Lou Gehrig’s disease, you will be automatically enrolled in Original Medicare the month you begin receiving your Social Security disability benefits.

  • If you have end-stage renal disease, you will not be automatically enrolled in Original Medicare. You can enroll yourself through the Social Security Administration.

What PDPs cover

Each Medicare Prescription drug plan has a list of covered drugs, which is known as a formulary.

Medicare drug plans place drugs into tiers. A drug in a lower tier will generally cost less than a drug in a higher tier.


Some costs you can expect to pay for your Medicare Prescription Drug Plan include:

  • Monthly premium

  • Yearly deductible

  • Copayments or coinsurance

The specific amounts you pay will vary depending on several factors, including:

  • The drugs you use

  • The Prescription Drug Plan you enroll in

  • Whether you go to a pharmacy in your plan’s network

  • Whether the drugs you use are on your plan’s formulary

  • Whether you get Extra Help paying your Part D costs

Prescription Drug Plans and Medicare Supplement Insurance

Medicare Prescription Drug Plans work with Original Medicare and Medicare Supplement Insurance to provide you with comprehensive health insurance coverage.

Medicare Supplement Insurance plans help cover some of your Medicare out-of-pocket costs, such as deductibles, copayments and coinsurance.

There are 10 standardized Medigap plans in most states, labeled A, B, C, D, F, G, K, L, M and N. Each Medigap plan provides a unique mix of benefits, but all 10 standardized plans offer at least partial coverage for:

  • Medicare Part A coinsurance and hospital costs

  • Medicare Part B coinsurance or copayment

  • First three pints of blood

  • Medicare Part A hospice care coinsurance or copayment

To learn more about Medicare Supplement Insurance plans and how they work with Medicare Prescription Drug Plans, call today to speak with a licensed agent.

Compare Medigap plans in your area.

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