This article provides general, evergreen education. Medicare rules, plan contracts, costs, and agency guidance can change. Confirm current information through the official sources listed below and the documents that apply to your own coverage.
A prescription drug plan is more than a list of premiums. Its formulary, tiers, pharmacy network, and management rules determine how a particular prescription is covered and what steps may be required.
Formulary
A formulary is a plan’s list of covered prescription drugs. Plans must meet Medicare coverage requirements, but each plan can choose many of the specific drugs it covers.
A plan may cover one drug in a class but not another, or cover a different formulation or strength.
Verify: Search the current formulary using the exact drug name, dosage, and form.
Drug tiers
Plans place drugs into tiers that generally correspond to different cost-sharing levels. The number and meaning of tiers can vary by plan.
A low tier is not a permanent classification, and the same drug may be placed differently by another plan.
Verify: Read the plan’s tier definitions and check the cost at the intended pharmacy.
Network and preferred pharmacies
Plans contract with pharmacy networks. Some network pharmacies are designated preferred and may offer lower plan-negotiated cost sharing than other network pharmacies.
“In network” and “preferred” are not the same. A familiar pharmacy may remain usable but cost more.
Verify: Compare local, specialty, and mail-order pharmacy options for the specific prescriptions.
Quantity limits
A quantity limit restricts how much of a covered drug the plan will cover over a stated period unless an exception is approved.
The limit may not match the prescriber’s intended quantity or travel needs.
Verify: Check the formulary notation and ask the plan or prescriber about the exception process before the medication is urgently needed.
Prior authorization
Prior authorization requires the plan to approve coverage based on specified criteria before the drug is covered. The prescriber may need to submit medical information.
A prescription at the pharmacy is not proof that authorization has been completed.
Verify: Track the request, decision date, and appeal instructions.
Step therapy
Step therapy generally requires trying one or more preferred drugs before the plan covers another drug, unless an exception is granted.
A person who previously succeeded on a medication may still encounter a step-therapy rule after changing plans.
Verify: Ask the prescriber whether clinical history supports an exception and follow the current plan process.
Formulary exceptions and transitions
Medicare drug plans have processes for requesting coverage exceptions and for certain transition supplies when a person enters a new plan or care setting.
A temporary fill is not a permanent coverage approval.
Verify: Use the time created by a transition supply to work with the prescriber and plan on a covered alternative or exception.
Common misunderstandings
- “Covered” means the same price at every pharmacy. Pharmacy status and tier matter.
- “A formulary listing guarantees an unlimited supply.” Quantity limits and other rules may apply.
- “A transition fill means the plan permanently approved the drug.” It is temporary.
Questions to consider
- Is the exact formulation and strength covered?
- What tier applies?
- Is my pharmacy preferred, standard network, or out of network?
- Do prior authorization, step therapy, or quantity limits apply?
- What are the exception and appeal steps?