Study Reveals Low but Rising Use of Esketamine Among Medicare Part D Enrollees
A study examining esketamine use among Medicare Part D beneficiaries reveals a significant yet uneven increase in prescribing rates across US states between 2019 and 2020. The analysis, which compared population-corrected prescription rates and spending data, sheds light on the early adoption of this novel antidepressant in the Medicare population.
Esketamine, a nasal spray approved for treatment-resistant depression, saw prescription rates rise from 13.0 to 41.6 per 100 000 Medicare Part D enrollees within 1 year. Despite this 2.6-fold increase—larger than the rise observed among Medicaid enrollees during the same period—the overall utilization remained low, consistent with pre-study expectations. Barriers such as the complexity of risk evaluation and mitigation strategy (REMS) requirements and limited facility infrastructure likely contributed to slow uptake.
Geographic disparities were pronounced, with between-state prescription rates varying by as much as 67-fold. Some states reported no esketamine prescribing activity at all. While 19 more municipalities reported prescribing in Medicare compared to Medicaid in 2019, that margin narrowed to 15 by 2020. The observed variability underscores ongoing inequities in access and implementation.
Notably, increased adoption may have been influenced by broader awareness, growing clinical evidence, and improved logistics for patient monitoring and staff training. Still, the researchers caution that these trends may not fully capture esketamine’s reach, as about a quarter of Medicare beneficiaries lack Part D coverage and patient-level indications were unavailable.
As Medicare covers the vast majority of Americans over age 65, these findings provide an early benchmark for esketamine’s increased use in older adult care. Ongoing data collection will be vital to track changes in utilization, assess the impact on patient outcomes, and address persistent regional disparities in access to this innovative therapy.
Reference
Cavanah LR. Increased use and state-level variation of esketamine prescriptions among medicare patients. Am J Psychiatry Resid J. 2025;20(3):6-10.doi:10.1176/appi.ajp-rj.2025.200302
