How to Choose the Best Medicare Part D Plan for Your Prescriptions

Picking a Medicare Part D plan isn’t about finding “the best” plan on the market — it’s about finding the best fit for your medications, budget, and pharmacy preferences. A low premium plan can still cost you more overall if it doesn’t cover your specific drugs well.

Start With Your Current Medications

Before comparing anything, make a simple list:

• Every prescription you take (exact name and dosage)
• How often you refill it
• Your preferred pharmacies (including any mail-order use)

This list is the foundation for your comparison. Part D plans differ most in which drugs they cover and how much they charge for each.

Check Each Plan’s Drug List and Tiers

Every Part D plan has a formulary (its list of covered drugs) and places drugs into tiers, which determine your copay or coinsurance.

When comparing plans:

• Confirm each of your drugs is on the formulary.
• Note the tier for each drug (e.g., Tier 1 preferred generic, Tier 2 generic, Tier 3 preferred brand, etc.).
• Look for drugs requiring prior authorization, step therapy, or quantity limits, which can delay or complicate access.

A plan with slightly higher premiums can be cheaper overall if your drugs are on lower tiers with lower copays.

Compare Total Annual Costs, Not Just Premiums

Focus on year-round cost, not only what you pay each month.

Review for each plan:

• Monthly premium: What you pay to have the coverage.
• Annual deductible: How much you must pay before the plan starts paying for most drugs.
• Copays/coinsurance: Your share of the cost at the pharmacy for each drug.
• Coverage gap (donut hole) impact: If you take several brand-name or expensive medications, check how your costs might change if you reach the coverage gap.

Use your medication list to estimate total annual spending under each plan, including premiums and out-of-pocket costs for drugs.

Look at Pharmacy Networks and Preferred Pharmacies

Plans often have preferred pharmacies where you pay lower copays.

Compare:

• Whether your usual pharmacy is in-network and preferred.
• The difference in cost between your pharmacy and a preferred pharmacy.
• Availability and terms of mail-order for maintenance medications.

Switching to a preferred or mail-order pharmacy can sometimes significantly reduce your total costs.

Consider Plan Stability and Flexibility

While coverage details can change each year, it’s still useful to look at:

• Star ratings for overall plan performance and member experience.
• Whether the plan offers extra support tools such as medication therapy management if you use multiple drugs.

Review your Part D coverage every year during the Medicare Open Enrollment Period, even if you’re happy with your current plan. Formularies, premiums, and cost-sharing can change, and a quick comparison can prevent surprises at the pharmacy counter.