(#40) How Same-Day Clozapine Levels can Improve Nonadherence Detection and Guide Treatment Strategies

Abstract: Antipsychotic nonadherence increases the risk of relapse, rehospitalization, and adverse outcomes for patients. Monitoring medication adherence is challenging because patient self-report and caregiver collateral is frequently unreliable. Clozapine nonadherence is especially challenging because missing two or more days of treatment requires re-titration to prevent adverse effects. Previously, clozapine levels at our institution were measured using a send-out test with a five-day turnaround. This delay prevented timely intervention. Since May 2023, the availability of in-house clozapine testing via an FDA-cleared turbidimetric immunoassay has improved prompt clinical decision-making by decreasing the result turnaround time from days to hours. This report presents four cases where same-day clozapine levels improved care for hospitalized patients. In each case, the patient struggled with chronic medication nonadherence, even with the presence of caregivers. In one case, rapid clozapine testing identified an adherent patient, allowing for immediate continuation of their prior-to-admission (PTA) dose. In the remaining three cases, testing revealed undetectable or subtherapeutic clozapine levels, requiring re-titration. In all four patients, rapid clozapine level testing was utilized throughout hospitalization to guide necessary dosage adjustments and treatment modifications. These cases illustrate how rapid clozapine testing can prevent unnecessary re-titration, improve patient safety, and guide treatment decisions for psychiatric inpatients receiving clozapine therapy.Short Description: This study identifies 4 recent cases in which rapid clozapine testing was used to confirm adherence or nonadherence and guide treatment during inpatient psychiatric hospitalization. Rapid testing for clozapine was implemented at our facility approximately two years ago, and has improved care for patients receiving clozapine.Name of Sponsoring Organization(s): Saladax Biomedical