OBJECTIVES: Treatment of schizophrenia and other psychotic disorders requires an individualized approach, often requiring use of antipsychotic medication to treat symptoms and prevent functional decline. Shortages and manufacturer discontinuations of antipsychotic medications place patients in vulnerable scenarios if medication cannot be accessed, leaving prescribers to alter therapy without guarantee of a sustained response to the new treatment. Our observational analysis aims to describe antipsychotic switches and utilization after a drug shortage or discontinuation is declared.

METHODS: Using Komodo Health data from January 1^st, 2016-September 11^th, 2023, we identified individuals with prescription claims for oral first-generation antipsychotics that were in shortage or were discontinued. Individuals were required to have six months of continuous treatment and no inpatient psychiatric hospitalizations prior to the shortage or discontinuation index date (i.e., initial shortage date listed by the United States Food and Drug Administration). The primary outcome was the proportion of medication switching within one year of the shortage or discontinuation date. The secondary outcome was a description of antipsychotic utilization.

RESULTS: A total of 112,804 individuals [mean age=52 years, 52% male] were selected for inclusion into the sample. Approximately half of the sample (49.8%) were Medicare prescription drug beneficiaries. As a result of a shortage or discontinuation, all individuals (100%) treated with loxapine (n=1636), molindone (n=13), thioridazine (n=1587), and trifluoperazine (n=3939) switched to another antipsychotic. Furthermore, these individuals had no claims for their original treatment during the one-year follow-up. Among individuals initially receiving treatment with thiothixene (n=5752), 61.6% started a different antipsychotic within one year. Individuals utilizing pimozide (9.6%) and perphenazine (16.1%) had lower switch rates. Quetiapine, risperidone, aripiprazole, and olanzapine were the most common antipsychotics initiated following a shortage or discontinuation.

CONCLUSIONS: Shortages acutely changed utilization patterns of first-generation antipsychotics, resulting in multiple individuals switching treatments immediately following the official declaration of a shortage or discontinuation.