How to compare prescription drug coverage in Medicare Advantage

Written by the My Plan Compass team. Last reviewed October 26, 2026, against Medicare.gov.

The same drug can cost very different amounts in two plans. It depends on whether the drug is on the plan's list of covered drugs, which price tier it is on, any rules the plan puts on it, and which pharmacy you use. Check each of your drugs in each plan you are considering, at the pharmacy you actually use.

What changes the price

The drug list. Each plan has its own list of covered drugs, called a formulary. A drug that is not on it is generally not covered.
The tier. Plans sort drugs into tiers. Generally, a drug in a lower tier costs you less than one in a higher tier, and plans divide their tiers differently (Medicare.gov: How drug plans work).
The exact drug. Brand name and generic, and different strengths and forms of the same medicine, can be on different tiers.
The pharmacy. Plans have pharmacy networks, and many charge less at their preferred pharmacies. A pharmacy outside the network may not be covered.

Rules a plan can put on a drug

Prior authorization: The plan must approve the drug before it covers it.
Step therapy: You must try a less expensive drug first. If it does not work for you, the plan covers the one your doctor prescribed.
Quantity limits: The plan covers only a set amount over a period, for example 30 tablets a month.

You or your prescriber can ask the plan for an exception to any of these, or to cover a drug that is not on its list. Your prescriber usually has to send a statement supporting the request. Source: Medicare.gov: Drug plan rules.

Limits that protect you in 2027

A yearly cap. Once you have paid $2,400 out of pocket for covered drugs in 2027 ($2,100 in 2026), you pay nothing more for covered drugs that year.
A deductible limit. No Medicare drug plan can have a deductible above $700 in 2027 ($615 in 2026), and some have none.
Insulin. A one-month supply of each covered insulin costs no more than $35, with no deductible (Medicare.gov: Insulin).
Spreading the cost. The Medicare Prescription Payment Plan lets you pay your drug costs in monthly amounts across the year. It does not lower what you pay.

Source: Medicare.gov: Drug coverage costs. If you have limited income, Extra Help can lower these costs further.

How My Plan Compass prices your drugs

You pick the exact drug, strength and form, and the pharmacy you use. We price each one in each plan from the plan's drug list and cost sharing, and add it to the plan's estimated yearly cost. Some 2027 prices are estimates until Medicare publishes its 2027 pricing files, and each plan says so when that is the case. We do not yet show prior authorization, step therapy or quantity limits, so check the plan's drug list for those. More in how we compare plans.

This guide is general information, not advice about your situation. We are not connected with or endorsed by the U.S. government or the federal Medicare program.