A coinsurance cost-share amount is a percentage of the total prescription cost. Implementing coinsurance cost sharing requires clear and frequent member communication to minimize member dissatisfaction. The advantage of the approach is that it buffers the employer from prescription drug cost inflation and the need to increase copays every year. Employers often add a dollar minimum and maximum. For example, a preferred brand prescription cost share might be 25% of the total prescription cost with a $20 minimum per prescription. A different employer might not set a minimum but set a maximum so its member would pay 25% of the cost of the drug with a maximum of $150 to be paid by the member.
Average retail 30 coinsurance ranged from a low of 21% for generics to 39% for nonpreferred brands, to 64% for lifestyle drugs (Table 17). When the design included minimums and/or maximum copays, the copays increased along with the tier as well. The average minimum copay for preferred brands was $22 while the average maximum copay was $270. Across all categories, average coinsurance rates were lower than in 2010, the greatest decrease being observed for generic drugs (Table 18).
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