Health Insurance

Drug Tier

Drug tiers rank medications from cheapest (generics) to most expensive (specialty drugs), with your copay or coinsurance rising as tiers increase.

Last reviewed: May 2026 · Editorial methodology

Definition

Drug tiers are the cost-sharing categories that health insurers and Medicare Part D plans use to organize formulary medications. Most plans use four to six tiers: Tier 1 covers preferred generic drugs with the lowest copays (often $0–$15), Tier 2 covers non-preferred generics, Tier 3 covers preferred brand-name drugs, Tier 4 covers non-preferred brand-name drugs, and Tier 5 or higher covers specialty biologics — which can require coinsurance of 25–33% per fill rather than a flat copay. Specialty medications on top tiers can cost hundreds or thousands of dollars per fill without assistance programs. If your drug is on a higher tier, you can ask your prescriber to request a formulary exception, which asks the insurer to cover the drug at a lower tier cost-sharing level if no therapeutically equivalent lower-tier option exists. Manufacturer copay assistance cards cannot be used with Medicare plans, but Extra Help and other programs can significantly reduce specialty drug costs for eligible Medicare members. Always check tier placement and quantity limits before starting a new high-cost medication.

Where this term matters

Health Insurance →Medicare →

Tip

Glossary definitions are educational. Always check your own policy language — insurers can define common terms differently from one another. When in doubt, request a written explanation from your agent.

Related terms

FormularyA formulary determines which medications your insurance covers and at what cost-sharing level, making it critical to review before choosing a plan.Prior AuthorizationPrior authorization is an insurer's cost-control mechanism that can delay care if approval is not obtained in advance.Step TherapyStep therapy protocols require patients to try and fail on cheaper drugs or treatments before the insurer will cover a more expensive option.Extra Help (Low-Income Subsidy)Extra Help (also called the Low-Income Subsidy or LIS) dramatically lowers prescription drug costs for Medicare beneficiaries with limited income and resources.Medicare Part DMedicare Part D covers prescription drugs and features a $2,100 out-of-pocket cap in 2026, ending the coverage gap that previously left beneficiaries with full costs.

Related guides

Source: Cover Forge USA editorial team|Last verified: May 2026|Methodology
Definitions are educational and may be simplified. Always refer to your policy contract and consult a licensed agent for terms that affect coverage decisions.
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Cover Forge USA Editorial Team

Editorial Lead

This article was researched and written by the Cover Forge USA editorial team against federal sources (NAIC, CMS, FEMA, DOL, SSA, state DOIs) and standard policy forms. Bylines organize content by topic — they do not assert individual licensure. See our editorial-policy for details.

Reviewed June 2026

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