Trends in Formulary Restrictions for Long-Acting Injectable Antipsychotic Medications Among Medicare Drug Plans, 2019-2023.

Objective: Long-acting injectable antipsychotics (LAIAPs) enable safe and effective long-term management of chronic psychotic disorders but are underused in clinical practice. The authors examined whether Medicare formulary restrictions (prior authorization [PA] or step therapy) impose barriers to LAIAP uptake.

Methods: The authors analyzed formulary restrictions and patient cost-sharing for several LAIAPs and estimated the percentage of plans (N=2,494 were available per year) applying formulary restrictions. Analyses were stratified by Medicare Advantage, dual Medicare-Medicaid eligibility plans, and Part D plan group and weighted by the number of enrollees at the per-year, per-plan level.

Results: Application of formulary restrictions for LAIAPs was low (<12% requiring PA [apart from olanzapine] and <4% requiring step therapy) and decreased among nearly all plan types between 2019 and 2023.

Conclusions: Formulary restrictions do not appear to present a significant barrier to use of LAIAPs for psychiatric patients with Medicare prescription drug coverage. Additional research is needed to further understand factors influencing LAIAP use.