A drug formulary list is used by insurance companies to identify prescription drugs, both generic and brand name, that offer the greatest overall value. Drug formulary lists are broken into three tiers:
Tier 1: Usually includes generic medications and has a low to $0 copay.
Tier 2: Usually includes preferred brand-name medications and may result in a moderate copay.
Tier 3: Usually includes non-preferred brand-name medications and results in a high co-pay or may require a Prior Authorization.