Medicare Part D: Choosing a Drug Plan
How to compare Part D formularies, pharmacies, and total drug costs.
Part D is about your drugs
Part D plans differ mainly on formulary tiers, preferred pharmacies, deductibles, and how they handle the coverage stages. The best plan is the one that covers your specific medications at the lowest total annual cost.
Use Medicare.gov's plan finder with your full drug list and pharmacy preferences every year — last year's winner may not win again.
Watch the details
Check prior authorization, quantity limits, and whether your pharmacy is preferred. Specialty drugs can dominate total cost.
If you have Advantage with built-in drug coverage, you generally do not also buy a standalone Part D plan.
Frequently asked questions
- Is the cheapest Part D premium the best deal?
- Often no. A slightly higher premium can save hundreds if your drugs sit on better tiers.
- When can I change Part D plans?
- During Open Enrollment in the fall and in certain Special Enrollment Periods.
Sources
- Medicare.gov — the official U.S. government Medicare site · reviewed 2026-01-15
- Centers for Medicare & Medicaid Services (CMS) · reviewed 2026-01-15
- OLYRON HealthMatch editorial methodology — how we source and rate options · reviewed 2026-01-15
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