Medicare Spending on Brand-name Combination Medications vs Their Generic Constituents.

Importance: Brand-name combination drugs can be more expensive than the sum of their components, especially when the constituent products are available as generic medications. The potential savings that could be achieved using generic components is not known.

Objective: To estimate the additional cost to Medicare of prescribing brand-name combination medications instead of generic constituents.

Design, Setting, and Participants: Retrospective analysis for 2011 through 2016 using the Medicare data set of Part D beneficiaries prescribed any of the 1500 medications that accounted for the highest total spending in 2015. Brand-name combination drugs that had identical or therapeutically equivalent generic constituents were included.

Exposures: Brand-name, oral combination medications with constituents available either as generic drugs or therapeutically equivalent generic substitutes.

Main Outcomes and Measures: The estimated difference between the amount spent by Medicare on brand-name combination drugs and the estimated amount that would have been spent on substitutable generic components.

Results: Among the 1500 medications evaluated, 29 brand-name combination medications were separated into 3 mutually exclusive categories: constituents available as generic medications at identical doses (n = 20), generic constituents at different doses (n = 3), and therapeutically equivalent generic substitutes (n = 6). For the constituents available as generic medications at identical doses category, total spending by Medicare in 2016 on the brand-name combination products was $303 million and the estimated spending for the generic constituents would have been $68 million, which is an estimated difference of $235 million. For the generic constituents at different doses category, total spending by Medicare in 2016 on the brand-name combination products was $232 million and the estimated spending for the generic constituents would have been $13 million, which is an estimated difference of $219 million. For the therapeutically equivalent generic substitutes category, total spending by Medicare in 2016 on the brand-name combination products was $491 million and the estimated spending for the generic constituents would have been $20 million, which is an estimated difference of $471 million. In 2016, the estimated spending for the generic constituents for these 29 drugs would have been $925 million less than the estimated spending for the brand-name combinations. For the 10 most costly combination products available during the entire study period, the listed Medicare spending could have been an estimated $2.7 billion lower between 2011 and 2016 if the generic constituents had been prescribed.

Conclusions and Relevance: In 2016, the difference between the amount that the Medicare drug benefit program reported spending on brand-name combination medications and the estimated spending for generic constituents for the same number of doses was $925 million. Promoting generic substitution and therapeutic interchange through prescriber education and more rational substitution policies may offer important opportunities to achieve substantial savings in the Medicare drug benefit program.