Speak to a Licensed Sales Agent


Mon-Fri: 8:30 a.m. to 8:00 p.m. ET

Medicare Basics

Drugs Covered by Prescription Drug Plans

Each individual Prescription Drug plan (PDP) has its own covered prescription drug list, also known as a formulary. It is common for these plans to classify prescription drugs by tiers. Prescription drugs in lower tiers generally cost less than prescription drugs found in higher tiers.

Your plan may alter its formulary during the year. If these changes include a prescription drug you are taking, your plan has two options. One, it either must provide you written notice at least 60 days before the change takes place. Alternatively, it can give you a 60-day supply when you request a refill as well as provide written notice of the change.

Tiers and Co-payments

See below for an example of levels of tiers and the general cost associated with them. Please keep in mind, each plans’ tiers may structure differently. Check with your plan to learn more about its specific tier structure.

  • Tier 1/Lower co-payment: Most generic prescription drugs
  • Tier 2/Medium co-payment: Preferred, brand-name prescription drugs
  • Tier 3/Higher co-payment: Non-preferred, brand name prescription drugs
  • Specialty tier/Highest co-payment or co-insurance: Unique, high-cost prescription drugs

Medicare prescription drug plans may create their own formularies and don’t have to cover every Part D prescription drug. However, they may not create a "discriminatory" formulary that excludes specific prescription drugs in order to discourage certain beneficiaries from enrolling. If your plan won’t cover a prescription drug that you need, you can ask for a written explanation from your Medicare prescription drug plan. You can also ask for an exception.

Drugs Always Covered with Part D

Formularies generally must include at least two prescription drugs in each category, and cover almost all of the prescription drugs in these protected classes of prescription drugs:

  • HIV
  • AIDS
  • Antidepressant
  • Antipsychotic
  • Anticancer
  • Immunosuppressant
  • Anticonvulsant

Medicare Part D must cover all commercially available vaccines, when medically necessary to prevent illness, except for vaccines covered under Medicare Part B.