Medicare Part D: Prescription Drug Coverage Explained
The wrong Part D plan can cost you hundreds of dollars a year in unnecessary drug costs. I'll compare every plan available in your zip code against your specific medications — free.
What Is Medicare Part D?
Medicare Part D is the prescription drug benefit available to all Medicare beneficiaries. It's offered through private insurance companies approved by Medicare. Each plan has its own list of covered drugs (formulary), premiums, deductibles, and pharmacy network. Choosing the right plan requires comparing your specific medications against each plan's formulary and cost structure.
Part D plans change every year. Even if you're happy with your current plan, reviewing it annually during Open Enrollment (Oct 15 – Dec 7) can save you significant money.
How Part D Coverage Works
Deductible Phase
You pay 100% of drug costs until you meet your deductible (up to $590 in 2026). Many plans waive the deductible for preferred generics.
Initial Coverage Phase
You pay your plan's copays or coinsurance for covered drugs. Your plan pays the rest until total drug costs reach $2,000.
Catastrophic Coverage Phase
Once your out-of-pocket costs reach $2,000 (the new 2025+ cap), you pay $0 for covered drugs for the rest of the year — a major improvement under the Inflation Reduction Act.
Who Needs Part D?
Original Medicare enrollees
Part A and Part B do not cover most prescription drugs. You need a standalone Part D plan.
Medicare Supplement (Medigap) enrollees
Medigap plans do not include drug coverage. You must enroll in a separate Part D plan.
Medicare Advantage enrollees
Most Medicare Advantage plans include Part D drug coverage (MAPD plans). Check your plan before enrolling in a standalone Part D plan.
Low-income beneficiaries
You may qualify for Extra Help (Low Income Subsidy), which can reduce your Part D premiums and copays to near zero.
The Part D Late Enrollment Penalty
If you go 63 or more consecutive days without creditable drug coverage after becoming eligible for Part D, you'll face a permanent late enrollment penalty. The penalty is 1% of the national base beneficiary premium for every month you went without coverage — and it's added to your premium for as long as you have Part D.
Don't wait. Even if you take no medications today, enrolling in a low-cost Part D plan protects you from the penalty.
Part D Enrollment Periods
Initial Enrollment Period (IEP)
7 months around your 65th birthday
Your first opportunity to enroll in Part D. Enroll during this window to avoid the late enrollment penalty.
Annual Enrollment Period (AEP)
October 15 – December 7
Switch, drop, or enroll in a Part D plan each year. Changes take effect January 1.
Special Enrollment Period (SEP)
Varies by qualifying event
Triggered by losing creditable coverage, moving, or other qualifying life events.
Medicare Part D FAQ
Find the Right Part D Plan for Your Medications
I'll compare every Part D plan available in your zip code against your specific drug list — and find the one with the lowest total annual cost. Free, no obligation.