Guide
How a good agent compares Medicare drug plans (and how to check their work)
Two drug plans with the same premium can cost you very different amounts in a year, depending on your prescriptions and your pharmacy. Here's what a careful comparison covers, so you can tell whether you're getting one.
Last reviewed October 26, 2026. General information, not advice about any plan.
What a careful comparison checks
Every drug, at your dose
Whether each one is on the plan's drug list, and its tier. A different strength can be on a different tier.Your pharmacy
Whether it's in network, and whether it's a preferred pharmacy with lower costs. Mail order can change the price too.The whole year's cost
Premiums plus the deductible plus your share for each drug, added up for 12 months, not just the monthly premium.Rules on your drugs
Prior authorization, step therapy (trying a cheaper drug first) or quantity limits that could slow down a refill.
Words you'll hear
- Formulary
- The plan's list of covered drugs.
- Tier
- The cost level a drug is placed in. Lower tiers usually cost less.
- Deductible
- What you pay for covered drugs before the plan starts paying its share. Some plans have none.
- Preferred pharmacy
- A network pharmacy where the plan charges you less.
- Creditable coverage
- Drug coverage at least as good as Medicare's standard. Having it, for example from a job, avoids the late penalty.
Protections that cap your costs
- Since 2025, a yearly cap on what you pay out of pocket for covered drugs. Once you reach it, you pay nothing more for covered drugs that year.
- Since 2025, the Medicare Prescription Payment Plan, which lets you spread those costs into monthly payments.
- Since 2023, each covered insulin is capped at $35 for a month's supply.
Double-checking the comparison
Ask the agent for the comparison in writing, with each drug listed. You can rerun it yourself with Medicare's Plan Finder on Medicare.gov, or with your state's free SHIP counselor. If the numbers don't match, ask why before you enroll. Need someone to do the comparison? Find a licensed agent near you.
Common questions
Is the plan with the lowest premium the cheapest?
Not necessarily. What you pay for your specific drugs during the year, plus the deductible, often matters more than the premium.
Do I need to compare plans every year?
Yes. Plans can change their drug lists, tiers and costs every January. Check your Annual Notice of Change each fall and compare again during the October 15 to December 7 enrollment period.
What if my drug isn't covered?
Ask your doctor about a covered alternative, or ask the plan for an exception. A comparison done before you enroll should catch this.
Can I spread my drug costs over the year?
Yes. Since 2025, the Medicare Prescription Payment Plan lets you pay your out-of-pocket drug costs in monthly amounts instead of all at the pharmacy. Ask your plan.
Keep reading
- What to bring to your first meeting with a Medicare agentA one-page checklist: the cards, doctor list and prescriptions an agent needs to compare plans for you, plus what you should never hand over.
- Medicare Open Enrollment checklist: what to check before December 7A step-by-step checklist for the October 15 to December 7, 2026 Open Enrollment Period: what to read in your plan's letter, what's changing for 2027, what you can switch, and what happens if you do nothing.
- Extra Help and Medicare Savings Programs: who qualifies and how to applyTwo programs that cut Medicare costs for people with limited income: Extra Help for drug costs and state Medicare Savings Programs for premiums. The 2026 limits, what they pay, and how to apply for both at once.
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