The Urban Institute analyzed data on Medicaid-covered prescription fills for medications for opioid use disorder (OUD) 2010-2025.

The findings:

• Medicaid-covered buprenorphine fills rose roughly 10-fold (936,000 to 9.4 million) between 2010 and their peak in 2021, before easing to 8.2 million by 2025.
• States that have expanded Medicaid and have higher OUD rates have higher numbers of Medicaid-covered buprenorphine fills.
• The increase in prescription fills was overwhelmingly concentrated in states that expanded Medicaid under the Affordable Care Act (ACA), particularly those with higher OUD rates. States that expanded Medicaid early, before 2019, accounted for about 80% of all Medicaid buprenorphine fills 2010-2025. Among these states, those with the largest increases had the greatest OUD burdens.
• In 2021, an estimated 61% of Medicaid enrollees with OUD had gained their coverage through ACA expansions.
• By 2023, Medicaid was financing more than half of all OUD medications nationally.
• An estimated 59% of Medicaid enrollees with OUD received buprenorphine last year, an increase from about 36% in 2019.

The main point: These patterns demonstrate Medicaid’s important role in access to SUD treatment.

Why it’s important: Though HR 1’s new Medicaid restrictions include some narrow exemptions for people with substance use disorder, research shows that many people with OUD who remain eligible will likely struggle with the documentation required to prove eligibility. If they lose coverage, it could interrupt their access to buprenorphine and increase the risk of overdose death.