What is the role of a formulary in a Part D plan?

• A. It lists drugs covered and costs with prior authorizations or exclusions
• B. It lists all network providers
• C. It sets premium levels
• D. It determines eligibility for enrollment

Answer: (B)

A formulary is the plan’s official list of prescription drugs that are covered, plus how much you pay and any rules for accessing them. In a Part D plan, it shows which medications are covered, the cost-sharing by tier, and any utilization requirements like prior authorization, step therapy, or quantity limits, as well as drugs that are excluded. This is why it’s the best description of its role: it directly governs which drugs are eligible for coverage and under what conditions, helping you predict out-of-pocket costs and access. The provider network, not the formulary, relates to which doctors and pharmacies you can use; premiums are determined by the plan’s overall pricing, not by the drug list; and eligibility pertains to who can enroll, not which drugs are covered.