“…3,4 Background Health insurance formularies have grown over time from simple medication lists to complex medication and medical device formularies with specialty "tiers" and shared cost burden. 5 Formulary composition and variations are also health system or company specific, creating greater complexity. In tiered formularies, medications are placed into categories, or tiers, based on lower-cost preferred drugs, higher-cost nonpreferred drugs, quantity restrictions, and copay amounts.…”