Feasibility of clinical pharmacist-led CYP2C19 genotyping for patients receiving non-emergent cardiac catheterization in an integrated health system.

Objective: To assess the feasibility of clinical pharmacist-led CYP2C19 genotype-guided P2Y inhibitor antiplatelet drug therapy recommendations to cardiologists in an outpatient cardiology practice.

Methods: This was a prospective, open-labeled, single-arm study conducted in an integrated healthcare delivery system between March 1, 2013 and January 23, 2014. Patients requiring non-emergent cardiac catheterization were included. A clinical pharmacist provided interpretation and recommendations from genotyping results. The feasibility of implementing CYP2C19 genotype-guided antiplatelet therapy was assessed by the: 1) percentage of patients approached who consented to CYP2C19 genotyping, 2) percentage of patients with CYP2C19 genotyping results available prior to cardiac catheterization, and 3) percentage of clinical pharmacist CYP2C19 genotype-based antiplatelet recommendations accepted by cardiologists.

Results: Of the 43 patients identified for potential recruitment, 22 of these were eligible for study enrollment and 6 (27%) patients consented and received CYP2C19 genotyping. All patients had genotyping results available prior to catheterization and all clinical pharmacists' antiplatelet therapy recommendations were accepted by the patients' cardiologists. Three patients had the CYP2C19 wild-type (*1/*1) genotype and the clinical pharmacist recommended clopidogrel therapy. CYP2C19 variant genotypes (i.e., *1/*2, *1/*17, and *2/*17) were found in the other three patients; alternative antiplatelet therapy was recommended for the patient with the *1/*2 genotype, while clopidogrel was recommended for those with *1/*17 and *2/*17 genotypes.

Conclusion: A relatively small proportion of patients undergoing non-emergent cardiac catheterization consented to pharmacogenetic testing; however, their cardiologists were receptive to clinical pharmacists conducting such testing and providing corresponding pharmacotherapy recommendations. Future studies should identify patient barriers to pharmacogenetic testing.