Your Part D formulary determines whether your medications are covered and how much they cost. Here is how to read one before you enroll.
What is a Part D formulary?
A formulary is the official list of drugs a Part D plan covers, divided into pricing tiers — typically preferred generics, generics, preferred brands, non-preferred drugs, and specialty drugs. Lower tiers cost less. Every plan must cover at least two drugs in each therapeutic category and all drugs in six protected classes, including antidepressants, antipsychotics, anticonvulsants, immunosuppressants, cancer drugs, and HIV/AIDS drugs. Because formularies differ widely, a drug that is cheap on one plan may be expensive or excluded on another. Always verify your medications before choosing a plan; 1-800-MEDIGAP can check them for you.
What if my drug is not on the formulary?
If a plan does not cover your medication, you have options. You can ask your doctor about a covered alternative, request a formulary exception with supporting documentation, or choose a different plan that covers your drug. Some drugs are covered but carry restrictions like prior authorization, step therapy, or quantity limits. Formularies can change during the year, though plans must give notice. The simplest fix is comparing plans by your actual drug list each fall. A licensed agent at 1-800-MEDIGAP can find a plan that covers your prescriptions.