The list of medications your insurance plan agrees to cover, usually sorted into tiers that determine your copay. If a drug isn't on the formulary, you'll pay full price unless you win a formulary exception. Formularies change yearly and mid-year, which is why people are sometimes forced to switch GLP-1s even when their current one is working.
Related terms: Formulary exclusion · Step therapy · Prior authorization (PA)
See also: Appeal letter templates