Variation in Generic Drug Manufacturers' Product Characteristics

Studies suggest appearance may be an important factor in medication nonadherence. This study was undertaken to characterize the range of appearances and costs of 16 oral solid generic medications in four major chronic diseases/conditions.

We identified frequently prescribed medications in four therapeutic classes-antidiabetics, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins), beta blockers, and heart failure drugs-and verified that each had at least three generic manufacturer sources in 2016. The color, shape, scoring, and size for each formulation were compared. Prices were determined based on manufacturers' self-reported wholesale acquisition costs effective December 31, 2016.

We identified 40 unique manufacturers for the antidiabetics, 35 for the statins, 38 for the beta blockers, and 71 for the heart failure agents. For all 16 drugs across all four disease states, there was an average of three colors, two shapes, 11 manufacturers, and four appearances when color and shape together are considered. The cost variance per drug ranged from 2% to more than 62,253%.

Substantial appearance variation among generically equivalent products raises the strong possibility that patients may experience product switches that could increase the likelihood of nonadherence. Our data support the need to further study drug appearance changes and interventions as a potential factor affecting chronic disease adherence outcomes.