Medicare Drug Tiers Explained: What Tier 1, 2, 3 and Specialty Mean

Reviewed October 2, 2026. Medicare drug tiers are the cost levels a Part D or Medicare Advantage drug plan uses to sort the drugs on its formulary (drug list). Tier 1 usually holds the lowest-cost generic drugs, and each higher tier generally costs you more, up to a specialty tier for very high-cost drugs. Your copay or coinsurance depends on which tier your drug is on, so the same medicine can cost very different amounts in two plans.

Quick answer: Look up each of your drugs in the plan’s formulary, note its tier and any restrictions, then compare the yearly cost in the Medicare Plan Finder. If your drug is on a high tier, ask your doctor about a lower-tier alternative or ask the plan for a tiering exception.

Medicare drug tier list: what each tier means

Medicare.gov gives this example of how a plan might set up its tiers:

Plans can use more tiers than this example, for instance splitting generics into “preferred generic” and “generic,” and tier names vary. The plan’s own formulary is the only list that counts, and it can differ from plan to plan even for the same drug.

What are tier 1 drugs?

Tier 1 drugs are usually common generics, such as many blood pressure, cholesterol and diabetes medicines. They’re the cheapest drugs on a plan’s list, and some plans charge $0 or a few dollars for a 30-day supply at a preferred pharmacy. Because each plan sets its own formulary, a generic on tier 1 in one plan could be on tier 2 in another.

How tier placement affects what you pay

Your cost for a drug depends on its tier, whether you’ve met the plan’s deductible, which pharmacy you use, and the payment stage you’re in. Key 2026 and 2027 Part D limits set by CMS:

Many plans don’t apply the deductible to tier 1 and tier 2 drugs, so you pay the tier copay right away. Once your out-of-pocket spending on covered drugs reaches the yearly cap, you pay $0 for covered Part D drugs for the rest of the year. Covered insulin costs no more than $35 for a month’s supply. Learn more in Medicare Part D drug coverage phases.

Preferred vs. standard pharmacies

Many plans charge less at “preferred” network pharmacies. A tier 1 generic might cost $0 at a preferred pharmacy and more at a standard one, so check the pharmacy column in the plan’s cost chart.

Rules that can apply to drugs on any tier

• Prior authorization: you or your prescriber must get the plan’s approval before it will cover the drug.
• Step therapy: you must try a lower-cost drug first.
• Quantity limits: the plan limits how much you can get at a time.

These rules are marked on the formulary. If one applies, your prescriber can ask the plan for an exception.

How to ask for a tiering exception

Medicare.gov defines a tiering exception as “when a drug plan decides to charge a lower amount for a drug that’s on its non-preferred drug tier.” To request one:

1. Ask your prescriber for a supporting statement explaining why lower-tier alternatives won’t work for you.
2. Contact your plan (or have your prescriber submit the request) and ask for a tiering exception.
3. The plan must give you a decision within set time limits, faster if your health could be harmed by waiting.
4. If the plan says no, you can appeal. See Medicare.gov’s drug plan appeals page in the sources below.

Plans generally don’t grant tiering exceptions for drugs on the specialty tier.

Formularies change: check every fall

Medicare.gov notes that “a Medicare drug plan can make changes to its drug list during the year under guidelines set by Medicare.” Bigger changes usually happen at the start of a new year. Your plan’s Annual Notice of Change, mailed in late September, shows any tier changes for 2027. Then use Open Enrollment, October 15 to December 7, 2026, to switch plans if a better option covers your drugs at a lower tier. Our annual Medicare plan review checklist and plan comparison worksheet help you do that.

Tips to pay less for drugs on high tiers

• Ask your doctor whether a generic or a preferred brand on a lower tier would work.
• Use a preferred pharmacy or the plan’s mail-order option for maintenance drugs.
• Compare plans by total yearly cost, not just premium. See understanding Medicare drug plan premiums.
• If your income is limited, apply for Extra Help through Social Security.
• Ask whether a drug should be covered under Part B instead. See does Medicare Part B cover prescription drugs?
• Don’t drop drug coverage to save money; a gap can trigger the Part D late enrollment penalty.

Frequently asked questions

How many drug tiers do Medicare plans have?

Each plan decides. Medicare.gov’s example uses tier 1, tier 2, tier 3 and a specialty tier, and many plans use additional tiers.

Is tier 1 or tier 5 cheaper?

Lower tiers cost less. Tier 1 is usually the cheapest, and the highest-numbered or specialty tier is the most expensive.

Can a plan move my drug to a higher tier?

Yes. Plans can change their drug lists under Medicare rules, and they must notify affected members about certain changes. Most changes take effect January 1 and appear in the Annual Notice of Change.

What tier is insulin on?

It depends on the plan, but covered insulin costs no more than $35 for a one-month supply under Part D.

Where do I find my plan’s drug tiers?

In the plan’s formulary on its website, in your plan materials, or by entering your drugs in the Medicare Plan Finder at Medicare.gov.

This article is general information, not medical or individual insurance advice. Medicare365 is not affiliated with or endorsed by the U.S. government or the federal Medicare program.

Official sources

• Medicare.gov: How do drug plans work?
• Medicare.gov: Drug plan rules
• Medicare.gov: Appeals in a Medicare drug plan
• Medicare.gov: Medicare Costs 2026
• CMS: CY 2027 Rate Announcement (Part D benefit parameters)