Part D After the Redesign: A Real Cap, and a Payment Plan

Part D is Medicare's outpatient prescription drug benefit, delivered either through a standalone Prescription Drug Plan (PDP) alongside Original Medicare or bundled into a Medicare Advantage plan (MA-PD). Every plan uses a formulary organized into cost-sharing tiers, and every plan is regulated by CMS.

The 2025 structure

• Deductible: up to $590 (plans may charge less).
• Initial coverage: you pay tier-based cost-sharing (copays or coinsurance).
• Annual out-of-pocket cap: $2,000. After you hit it, covered drugs are $0 for the rest of the calendar year.
• Coverage gap ("donut hole"): eliminated as a distinct phase.

Medicare Prescription Payment Plan

New in 2025: enrollees can elect to spread their annual Part D out-of-pocket costs across monthly installments through their plan rather than paying at the pharmacy counter. This is most useful for people with a large early-in-year cost (e.g. a $1,200 specialty fill in January) they'd rather spread over 12 months. Opt in through the plan; there is no interest or fee.

Formularies and tiers

Every plan publishes a formulary — the list of covered drugs and their tier. Tiers typically range from Tier 1 (preferred generic, lowest copay) to Tier 5 (specialty, coinsurance often 25–33%). A plan can change its formulary during the year with 30 days' notice, subject to CMS rules.

The late-enrollment penalty

If you go 63 or more consecutive days without creditable prescription drug coverage after your Initial Enrollment Period, you'll owe a permanent penalty when you eventually enroll. The penalty is 1% of the national base beneficiary premium ($36.78 in 2025) per uncovered month, added to your Part D premium for life. Employer, VA and Tricare coverage typically qualify as creditable — get written confirmation from the plan sponsor.

How to pick a plan each fall

1. List every prescription with dosage and refill frequency.
2. Enter the list into Medicare's Plan Finder for your ZIP, including your preferred pharmacies.
3. Compare total annual cost — premium plus drug cost-sharing — not just premium.
4. Confirm each drug is on the formulary at a tier you can afford, with no utilization management (prior authorization, step therapy) that surprises you.
5. Re-shop every year during the Annual Election Period. Plans, prices, and formularies change.

Step-by-step: how to find a Part D plan with the Plan Finder, or start from the Medicare Plan Finder guide.

Frequently asked questions

How do I compare Part D plans and find the cheapest one for my drugs?

Enter every prescription with dosage and refill frequency into the Medicare Plan Finder at medicare.gov/plan-compare, add your pharmacies, and sort by lowest drug plus premium cost. The cheapest plan is specific to your drug list — the lowest premium is rarely the lowest total cost.

What is the Part D out-of-pocket cap in 2025?

Out-of-pocket spending on covered drugs is capped at $2,000 a year, and the donut hole coverage gap no longer exists. Plans must also offer the Medicare Prescription Payment Plan, which spreads that amount across monthly installments.

What is the Part D late-enrollment penalty?

If you go 63 days or more without creditable drug coverage after your Initial Enrollment Period, Medicare adds 1% of the national base beneficiary premium for each uncovered month, permanently, to your Part D premium.

Do I need Part D if I take no prescriptions?

Usually yes, because the penalty is permanent and the lowest-premium plan costs little. Enrolling in a minimal plan protects you against both a future prescription and a compounding penalty.