Hydralazine is a vasodilator typically used in the treatment of resistant hypertension and heart failure. N-acetyltransferase 2 (NAT2) catalyzes the metabolism of hydralazine into inactive metabolites. NAT2 poor metabolizers (historically referred to as "slow acetylators") are predicted to have increased plasma hydralazine concentrations compared with NAT2 rapid and intermediate metabolizers (historically referred to as "rapid acetylators" and "intermediate acetylators," respectively), which may lead to both increased clinical efficacy and adverse effects, including drug-induced systemic lupus erythematosus. This guideline summarizes the evidence from the literature relevant to NAT2/hydralazine and provides recommendations for hydralazine prescribing based on NAT2 genotype-predicted acetylator phenotype (updates at www.cpicpgx.org).

The University of Florida Health conducted a pragmatic implementation of a pharmacogenetics (PGx) panel-based test to guide medications used for supportive care prescribed to patients undergoing chemotherapy. The implementation was in the context of a pragmatic clinical trial for patients with non-hematologic cancers being treated with chemotherapy. Patients were randomized to either the intervention arm or control arm and received PGx testing immediately or at the end of the study, respectively. Patients completed the MD Anderson Symptom Inventory (MDASI) to assess quality of life (QoL). A total of 150 patients received PGx testing and enrolled in the study. Clinical decision support and implementation infrastructure were developed. While the study was originally planned for 500 patients, we were underpowered in our sample of 150 patients to test differences in the patient-reported MDASI scores. We did observed a high completion rate (92%) of the questionnaires; however, there were few medication changes (n = 6 in the intervention arm) based on PGx test results. Despite this, we learned several lessons through this pragmatic implementation of a PGx panel-based test in an outpatient oncology setting. Most notably, patients were less willing to undergo PGx testing if the cost of the test exceeded $100. In addition, to enhance PGx implementation success, reoccurring provider education is necessary, clinical decision support needs to appear in a more conducive way to fit in with oncologists' workflow, and PGx test results need to be available earlier in treatment planning.

Pharmacogenetics promises to optimize treatment-related outcomes by informing optimal drug selection and dosing based on an individual’s genotype in conjunction with other important clinical factors. Despite significant evidence of genetic associations with drug response, pharmacogenetic testing has not been widely implemented into clinical practice. Among the barriers to broad implementation are limited guidance for how to successfully integrate testing into clinical workflows and limited data on outcomes with pharmacogenetic implementation in clinical practice. The Pharmacogenomics Global Research Network Implementation Working Group seeks to engage institutions globally that have implemented pharmacogenetic testing into clinical practice or are in the process or planning stages of implementing testing to collectively disseminate data on implementation strategies, metrics, and health-related outcomes with the use of genotype-guided drug therapy to ultimately help advance pharmacogenetic implementation. This paper describes the goals, structure, and initial projects of the group in addition to implementation priorities across sites and future collaborative opportunities.

Purpose To describe the implementation of CYP2C19 testing into clinical practice at University of Florida (UF) Health Gainesville hospital to guide proton pump inhibitor (PPI) dosing and the lessons learned from this experience. Different CYP2C19 genotypes are associated with variability in PPI plasma concentrations and intragastric pH, which may contribute to the risk of treatment failure due to subtherapeutic concentrations and adverse effects (eg, infection, bone fracture, renal dysfunction) with sustained supratherapeutic concentrations. Based on evidence available prior to the availability of pertinent Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines, the UF Health Precision Medicine Program (PMP) developed clinical recommendations, provided through automated alerts at the time of a PPI order, to (1) increase the PPI dose for individuals with genotypes linked to increased CYP2C19 enzyme activity (ie, rapid and ultrarapid metabolizers) to improve the likelihood of drug effectiveness and (2) decrease the dose for individuals with decreased CYP2C19 activity (ie, intermediate and poor metabolizers) to reduce the risk of harm. The CYP2C19-PPI implementation was an iterative process that taught us key implementation lessons. Most notably, physician engagement is essential, problem lists in the medical record are unreliable, and special populations (eg, pediatric patients) need to be considered. Conclusion Guiding PPI prescribing based on CYP2C19 genotype is a practical approach to potentially improve the benefit-risk ratio with PPI therapy. Physician engagement is key for successful implementation. A CPIC guideline on CYP2C19 genotype-guided PPI dosing is now available, and automated alerts may be instituted to facilitate implementation.

Glucose‐6‐phosphate dehydrogenase (G6PD) deficiency is associated with development of acute hemolytic anemia in the setting of oxidative stress, which can be caused by medication exposure. Regulatory agencies worldwide warn against the use of certain medications in persons with G6PD deficiency, but in many cases, this information is conflicting, and the clinical evidence is sparse. This guideline provides information on using G6PD genotype as part of the diagnosis of G6PD deficiency and classifies medications that have been previously implicated as unsafe in individuals with G6PD deficiency by one or more sources. We classify these medications as high, medium, or low to no risk based on a systematic review of the published evidence of the gene–drug associations and regulatory warnings. In patients with G6PD deficiency, high‐risk medications should be avoided, medium‐risk medications should be used with caution, and low‐to‐no risk medications can be used with standard precautions, without regard to G6PD phenotype. This new document replaces the prior Clinical Pharmacogenetics Implementation Consortium guideline for rasburicase therapy in the context of G6PD genotype (updates at: www.cpicpgx.org).

INTRODUCTION: Dual-antiplatelet therapy (DAPT) is clinically indicated for patients undergoing endovascular procedures. Clopidogrel is the most commonly used P2Y12 inhibitor used for DAPT, and is a prodrug bioactivated by the CYP2C19 enzyme. Inferring platelet response can be done by genotyping CYP2C19 to determine metabolizer status. Patients with two functional alleles are considered normal metabolizers (NM), patients with one or two increased activity alleles are rapid (RM) or ultra-rapid metabolizers (UM), respectively, and patients with one or two loss-of-function (LOF) alleles are intermediate (IM) or poor metabolizers (PM), respectively. Another method of measuring antiplatelet response to clopidogrel is the VerifyNow Platelet assay (measured in platelet reactivity units [PRUs]), but the optimal range of PRUs in neuro-endovascular procedures has not yet been established. At UF Health, platelet reactivity testing is routine, but CYP2C19 genotyping is less frequent in patients undergoing these procedures. METHODS: Data were collected from the EMR patients who had a CYP2C19 genotype result ordered by the neurosurgical department. We assessed platelet reactivity tests and antiplatelet medication changes between different phenotype groups. Phenotypes included ultra-rapid, rapid, normal, intermediate and poor metabolizers. Patients were categorized as non-responders to clopidogrel if their platelet reactivity tests were >204 PRUs prior to medication change, hyper-responders if their platelet reactivity tests were <20 PRUs, and optimal responders if reactivity fell between 20-204 PRUs. RESULTS: 41 neurosurgical patients were genotyped. CYP2C19 phenotypes included ultra-rapid metabolizers (10%), rapid metabolizers (34%), normal metabolizers (37%), intermediate metabolizers (12%) and poor metabolizers (7%). Six patients had dose decreased to 75 mg QOD; 83% were hyper-responders. Three patients had their dose halved; 100% were hyper-responders. Four patients were switched to ticagrelor; 100% were clopidogrel non-responders. CONCLUSION: Patients who had their clopidogrel dose reduced were generally classified as hyper-responders based on platelet reactivity testing, and majority had increased CYP2C19 enzyme activity based on genotype. Of the non-responders who had a medication change to alternative P2Y12 therapy,majority had decreased CYP2C19 enzyme activity.

Neurodevelopmental disorders have steadily increased in incidence in the United States. Over the past decade, there have been significant changes in clinical diagnoses and treatments some of which are due to the increasing adoption of pharmacogenomics (PGx) by clinicians. In this pilot study, a multidisciplinary team at the Arkansas Children’s Hospital North West consulted on 27 patients referred for difficult-to-manage neurodevelopmental and/or neurobehavioral disorders. The 27 patients were evaluated by the team using records review, team discussion, and pharmacogenetic testing. OneOme RightMed® (Minneapolis, MN, USA) and the Arkansas Children’s Hospital comprehensive PGx test were used for drug prescribing guidance. Of the 27 patients’ predicted phenotypes, the normal metabolizer was 11 (40.8%) for CYP2C19 and 16 (59.3%) for CYP2D6. For the neurodevelopmental disorders, the most common comorbid conditions included attention-deficit hyperactivity disorder (66.7%), anxiety disorder (59.3%), and autism (40.7%). Following the team assessment and PGx testing, 66.7% of the patients had actionable medication recommendations. This included continuing current therapy, suggesting an appropriate alternative medication, starting a new therapy, or adding adjunct therapy (based on their current medication use). Moreover, 25.9% of patients phenoconverted to a CYP2D6 poor metabolizer. This retrospective chart review pilot study highlights the value of a multidisciplinary treatment approach to deliver precision healthcare by improving physician clinical decisions and potentially impacting patient outcomes. It also shows the feasibility to implement PGx testing in neurodevelopmental/neurobehavioral disorders.

Abstract Background Despite the increased demand for pharmacogenetic (PGx) testing to guide antidepressant use, little is known about how to implement testing in clinical practice. Best–worst scaling (BWS) is a stated preferences technique for determining the relative importance of alternative scenarios and is increasingly being used as a healthcare assessment tool, with potential applications in implementation research. We conducted a BWS experiment to evaluate the relative importance of implementation factors for PGx testing to guide antidepressant use. Methods We surveyed 17 healthcare organizations that either had implemented or were in the process of implementing PGx testing for antidepressants. The survey included a BWS experiment to evaluate the relative importance of Consolidated Framework for Implementation Research (CFIR) constructs from the perspective of implementing sites. Results Participating sites varied on their PGx testing platform and methods for returning recommendations to providers and patients, but they were consistent in ranking several CFIR constructs as most important for implementation: patient needs/resources, leadership engagement, intervention knowledge/beliefs, evidence strength and quality, and identification of champions. Conclusions This study demonstrates the feasibility of using choice experiments to systematically evaluate the relative importance of implementation determinants from the perspective of implementing organizations. BWS findings can inform other organizations interested in implementing PGx testing for mental health. Further, this study demonstrates the application of BWS to PGx, the findings of which may be used by other organizations to inform implementation of PGx testing for mental health disorders.

IntroductionClinical pharmacogenomics is a required element in the Doctor of Pharmacy (Pharm.D.) curriculum. However, pharmacogenomics is not widely adopted into clinical practice and as such, considerable variability in clinical teaching and learning activities within pharmacogenomic advanced pharmacy practice experiences (APPE) exist. Among other places in the University of Florida's Pharm.D. curriculum, practical applications of clinical pharmacogenomics are covered during the APPE year through an elective 6-week Clinical Pharmacogenomics APPE. ObjectivesDescribe our analysis of clinical pharmacogenomics competency statements and our process of matching these statements with learning activities in our APPE to: (a) identify unmet needs, and (b) identify essential activities for a clinical pharmacogenomics APPE for students to meet pharmacogenomics competencies. MethodsWe reviewed previous APPE syllabi to identify APPE activities, conducted a literature search to identify recommendations on clinical pharmacogenomics competencies, and then aligned these two components. A gap analysis was conducted by preceptors to determine the need for additional activities. ResultsTwenty APPE activities and 42 competency statements were identified. Eighty-six percent of competency statements were matched to one or more APPE activities. Three activities were added to our Clinical Pharmacogenomics APPE. ConclusionWe refined our Clinical Pharmacogenomics APPE to ensure students meet all of the identified competency statements and provided an essential list of APPE activities that, if implemented, will meet these competency statements.

There is growing interest in utilizing pharmacogenetic (PGx) testing to guide antidepressant use, but there is lack of clarity on how to implement testing into clinical practice. We administered two surveys at 17 sites that had implemented or were in the process of implementing PGx testing for antidepressants. Survey 1 collected data on the process and logistics of testing. Survey 2 asked sites to rank the importance of Consolidated Framework for Implementation Research (CFIR) constructs using best-worst scaling choice experiments. Of the 17 sites, 13 had implemented testing and four were in the planning stage. Thirteen offered testing in the outpatient setting, and nine in both outpatient/inpatient settings. PGx tests were mainly ordered by psychiatry (92%) and primary care (69%) providers. CYP2C19 and CYP2D6 were the most commonly tested genes. The justification for antidepressants selected for PGx guidance was based on Clinical Pharmacogenetics Implementation Consortium guidelines (94%) and US Food and Drug Administration (FDA; 75.6%) guidance. Both institutional (53%) and commercial laboratories (53%) were used for testing. Sites varied on the methods for returning results to providers and patients. Sites were consistent in ranking CFIR constructs and identified patient needs/resources, leadership engagement, intervention knowledge/beliefs, evidence strength and quality, and the identification of champions as most important for implementation. Sites deployed similar implementation strategies and measured similar outcomes. The process of implementing PGx testing to guide antidepressant therapy varied across sites, but key drivers for successful implementation were similar and may help guide other institutions interested in providing PGx-guided pharmacotherapy for antidepressant management.

Purpose The increased availability of clinical pharmacogenetic (PGx) guidelines and decreasing costs for genetic testing have slowly led to increased utilization of PGx testing in clinical practice. Pre-emptive PGx testing, where testing is performed in advance of drug prescribing, is one means to ensure results are available at the time of prescribing decisions. However, the most efficient and effective methods to clinically implement this strategy remain unclear. Methods In this report, we compare and contrast implementation strategies for pre-emptive PGx testing by 15 early-adopter institutions. We surveyed these groups, collecting data on testing approaches, team composition, and workflow dynamics, in addition to estimated third-party reimbursement rates. Results We found that while pre-emptive PGx testing models varied across sites, institutions shared several commonalities, including methods to identify patients eligible for testing, involvement of a precision medicine clinical team in program leadership, and the implementation of pharmacogenes with Clinical Pharmacogenetics Implementation Consortium guidelines available. Finally, while reimbursement rate data were difficult to obtain, the data available suggested that reimbursement rates for pre-emptive PGx testing remain low. Conclusion These findings should inform the establishment of future implementation efforts at institutions considering a pre-emptive PGx testing program.

A formal assessment of pharmacogenomics clinical decision support (PGx-CDS) by providers is lacking in the literature. The objective of this study was to evaluate the usability of PGx-CDS tools that have been implemented in a healthcare setting. We enrolled ten prescribing healthcare providers and had them complete a 60-min usability session, which included interacting with two PGx-CDS scenarios using the "Think Aloud" technique, as well as completing the Computer System Usability Questionnaire (CSUQ). Providers reported positive comments, negative comments, and suggestions for the two PGx-CDS during the usability testing. Most provider comments were in favor of the current PGx-CDS design, with the exception of how the genotype and phenotype information is displayed. The mean CSUQ score for the PGx-CDS overall satisfaction was 6.3 ± 0.95, with seven strongly agreeing and one strongly disagreeing for overall satisfaction. The implemented PGx-CDS at our institution was well received by prescribing healthcare providers. The feedback collected from the session will guide future PGx-CDS designs for our healthcare system and provide a framework for other institutions implementing PGx-CDS.

CYP2D6 genotype is increasingly being integrated into practice to guide prescribing of certain medications. The CYP2D6 drug metabolizing enzyme is susceptible to inhibition by concomitant drugs, which can lead to a clinical phenotype that is different from the genotype-based phenotype, a process referred to as phenoconversion. Phenoconversion is highly prevalent but not widely integrated into practice because of either limited experience on how to integrate or lack of knowledge that it has occurred. We built a calculator tool to help clinicians integrate a standardized method of assessing CYP2D6 phenoconversion into practice. During tool-building, we identified several clinical factors that need to be considered when implementing CYP2D6 phenoconversion into clinical practice. This tutorial shares the steps that the University of Florida Health Precision Medicine Program took to build the calculator tool and identified clinical factors to consider when implementing CYP2D6 phenoconversion in clinical practice.

We aimed to determine the potential value of panel-based pharmacogenetic (PGx) testing in patients with chronic pain or gastroesophageal reflux disease (GERD) who underwent single-gene PGx testing to guide opioid or proton pump inhibitor (PPI) therapy, respectively. Of 448 patients included (chronic pain, n = 337; GERD, n = 111), mean age was 57 years, 68% were female, and 73% were white. Excluding opiates for the pain cohort and PPIs for the GERD cohort, 76.6% of patients with pain and 71.2% with GERD were prescribed at least one additional medication with a high level of PGx evidence, most commonly ondansetron or selective serotonin reuptake inhibitors. The most common genes that could inform PGx drug prescribing were CYP2C19, CYP2D6, CYP2C9, and SLCO1B1. Our findings suggest that patients with chronic pain or GERD are commonly prescribed drugs with a high level of evidence for a PGx-guided approach, supporting panel-based testing in these populations.

Background: Despite its approval in 1953, hydralazine hydrochloride continues to be used in the management of resistant hypertension, a condition frequently managed by nephrologists and other clinicians. Hydralazine hydrochloride undergoes metabolism by the N-acetyltransferase 2 (NAT2) enzyme. NAT2 is highly polymorphic as approximately 50% of the general population are slow acetylators. In this review, we first evaluate the link between NAT2 genotype and phenotype. We then assess the evidence available for genotype-guided therapy of hydralazine, specifically addressing associations of NAT2 acetylator status with hydralazine pharmacokinetics, antihypertensive efficacy, and toxicity. Summary: There is a critical need to use hydralazine in some patients with resistant hypertension. Available evidence supports a significant link between genotype and NAT2 enzyme activity as 29 studies were identified with an overall concordance between genotype and phenotype of 92%. The literature also supports an association between acetylator status and hydralazine concentration, as fourteen of fifteen identified studies revealed significant relationships with a consistent direction of effect. Although fewer studies are available to directly link acetylator status with hydralazine antihypertensive efficacy, the evidence from this smaller set of studies is significant in 7 of 9 studies identified. Finally, 5 studies were identified which support the association of acetylator status with hydralazine-induced lupus. Clinicians should maintain vigilance when prescribing maximum doses of hydralazine. Key Messages: NAT2 slow acetylator status predicts increased hydralazine levels, which may lead to increased efficacy and adverse effects. Caution should be exercised in slow acetylators with total daily hydralazine doses of 200 mg or more. Fast acetylators are at risk for inefficacy at lower doses of hydralazine. With appropriate guidance on the usage of NAT2 genotype, clinicians can adopt a personalized approach to hydralazine dosing and prescription, enabling more efficient and safe treatment of resistant hypertension.

Pharmacogenetic testing (PGT) is increasingly being used as a tool to guide clinical decisions. This article describes the development of an outpatient, pharmacist-led, pharmacogenetics consult clinic within internal medicine, its workflow, and early results, along with successes and challenges. A pharmacogenetics-trained pharmacist encouraged primary care physicians (PCPs) to refer patients who were experiencing side effects/ineffectiveness from certain antidepressants, opioids, and/or proton pump inhibitors. In clinic, the pharmacist confirmed the need for and ordered CYP2C19 and/or CYP2D6 testing, provided evidence-based pharmacogenetic recommendations to PCPs, and educated PCPs and patients on the results. Operational and clinical metrics were analyzed. In two years, 91 referred patients were seen in clinic (mean age 57, 67% women, 91% European-American). Of patients who received PGT, 77% had at least one CYP2C19 and/or CYP2D6 phenotype that would make conventional prescribing unfavorable. Recommendations suggested that physicians change a medication/dose for 59% of patients; excluding two patients lost to follow-up, 87% of recommendations were accepted. Challenges included PGT reimbursement and referral maintenance. High frequency of actionable results suggests physician education on who to refer was successful and illustrates the potential to reduce trial-and-error prescribing. High recommendation acceptance rate demonstrates the pharmacist’s effectiveness in providing genotype-guided recommendations, emphasizing a successful pharmacist–physician collaboration.