The short answer
Every Part D plan sorts its covered drugs into tiers, and the tier a drug is on sets your copay. Lower tiers — usually preferred generics — cost the least; higher tiers — brand-name and specialty drugs — cost more. The same medication can be on different tiers across plans, which is a big reason your drug costs vary from plan to plan.
Understanding tiers helps you predict your costs and spot chances to pay less.
How tiers set your cost
A typical plan has several tiers, from preferred generics up through non-preferred and specialty drugs, each with its own copay or coinsurance. A generic on tier 1 might cost a few dollars, while a brand on a higher tier costs much more. Because plans place the same drug differently, the tier is where a lot of the price difference between plans lives.
Our guide to Part D formularies and drug tiers shows how to read a plan's tier structure so you know what each of your drugs will cost.
How to move to a cheaper tier
The most reliable way to lower a drug's tier cost is to ask your doctor whether a generic or a therapeutically similar lower-tier drug would work for you — often it will, at a fraction of the cost. You can also compare plans that place your specific drugs on lower tiers. If a needed drug is on a high tier with no alternative, a formulary exception is sometimes possible.
Small tier changes across a few regular prescriptions add up over a year. Our doctor and drug coverage tool helps you find the plan that tiers your drugs most favorably.
Frequently Asked Questions
What are Part D drug tiers?
Categories a plan sorts covered drugs into, each with its own copay. Lower tiers (preferred generics) cost the least; higher tiers (brand and specialty drugs) cost more.
Why does the same drug cost different amounts on different plans?
Because plans place the same drug on different tiers. A drug that's a low-cost tier on one plan may be a higher tier on another, changing your copay.
How can I lower my drug tier costs?
Ask your doctor about generic or lower-tier alternatives, compare plans that tier your drugs favorably, and consider a formulary exception if a needed drug is high-tier with no alternative.
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