PT-024 - EVALUATION OF PRESCRIBER BEHAVIOR IN RESPONSE TO CYP2C19-CLOPIDOGREL BEST PRACTICE ALERTS.

A. Springer¹, Y. Gafari¹, T. Smith², E. Tillman², T. Skaar³, T. Shugg³; ¹Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA, ²Indiana University School of Medicine, Indianapolis, IN, USA, ³Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.

Background: Clopidogrel, a widely used antiplatelet, is mainly bioactivated by Cytochrome P450 2C19 (CYP2C19). Genetic variants in CYP2C19 cause altered clopidogrel bioactivation, resulting in reduced antiplatelet effect in intermediate metabolizers (IMs) and poor metabolizers (PMs). In 2020, Indiana University Health implemented interruptive PGx best practice alerts (BPAs) in the electronic health record (EHR) to recommend alternative antiplatelets for CYP2C19 IMs and PMs; if prescribers continued clopidogrel, an override reason was required. Objectives of this study were to (1) evaluate prescribing behavior in response to CYP2C19-clopidogrel BPAs and (2) determine the reasons that BPAs were overridden.

Methods: An EHR report was created to identify patients from 2020 to December 2023 that had a CYP2C19-clopidogrel BPA fire. For those patients, additional EHR reports were created and manual data collection was performed to (1) determine prescriber response to the BPA, (2) record all medications prescribed within 15 minutes following BPA firing, and (3) record all prescriptions for P2Y12 inhibitor antiplatelets in the year following the date of first BPA firing. Patients were analyzed until the occurrence of any of the following: discontinuation of P2Y12 inhibitors; death from any cause; 1 year from the first BPA date.

Results: CYP2C19-clopidogrel BPAs fired for 180 patients, with 2.3 ± 1.8 (mean ± SD) BPAs per patient. Inpatient orders or outpatient prescriptions for clopidogrel, ticagrelor, and prasugrel, were written for 157, 55, and 24 unique patients, respectively. As displayed in Figure 1, study patients were prescribed clopidogrel for 71.6% of study days, ticagrelor for 19.4%, and prasugrel for 9.0%. The most common BPA override reason was selection of the radio button for “Provider Clinical Judgment” in 121 patients. Other common free-text override reasons were home medication (33) and cardiology/MD aware (18).

Conclusion: Despite the implementation of BPAs recommending alternative therapy, clopidogrel was the most prescribed P2Y12 inhibitor in CYP2C19 IMs and PMs. The most common BPA override reasons included provider clinical judgment and reluctance to switch therapy. Based on these findings, additional follow up is needed to determine the reasoning for the provider clinical judgement.