Prescription medications with actionable pharmacogenomic recommendations in Veterans Health Administration patients.

Aim: To evaluate the prevalence of medications with actionable pharmacogenomic (PGx) safety and efficacy recommendations in patients receiving care from the Veterans Health Administration. Materials & methods: Outpatient prescription data from 2011 to 2021 and any documented adverse drug reactions (ADRs) were reviewed for those who received PGx testing at one Veterans Administration location between November 2019 and October 2021. Results: Among the reviewed prescriptions, 381 (32.8%) were associated with an actionable recommendation based on the Clinical Pharmacogenetics Implementation Consortium (CPIC) prescribing guidelines, with 205 (17.7%) for efficacy concerns and 176 (15.2%) for safety concerns. Among those with a documented ADR for a PGx-impacted medication, 39.1% had PGx results that aligned with CPIC recommendations. Conclusion: Medications with actionable PGx recommendations for safety and efficacy concerns are received with similar frequency, and most patients who have undergone PGx testing at the Phoenix Veterans Administration have received medications that may be impacted by PGx testing.

Identifying End Users' Preferences about Structuring Pharmacogenetic Test Orders in an Electronic Health Record System.

Pharmacogenetics (PGx) testing can be used for detecting genetic variations that may affect an individual's anticipated metabolism of, or response to, medications. Although several studies have focused on developing tools for delivering results from PGx testing, there is a relative dearth of information about how to design provider-friendly electronic order-entry systems for PGx. The U.S. Department of Veterans Affairs (VA) is preparing to implement a new electronic health records system. In this study, VA PGx test end users were surveyed about their preferences for how electronic test orders for PGx should be structured, including the nomenclature that should be used to search for and identify PGx-test orders, whether to offer single- versus multigene tests, and whether information about test methodology should be included in the order name. Responses were analyzed systematically to identify areas of agreement and disagreement with the survey options, and areas where respondents' opinions diverged. End users endorsed preferences for flexible ways to identify and order PGx tests and multigene panel tests; opinions on whether test methodology should be included in the test name were divergent. The results could be used for both informing the VA's new electronic health records implementation (including how PGx tests are searched for and ordered) and for providing insights for other health systems implementing PGx-testing programs.

Summary of Torsades de Pointes (TdP) Reports Associated with Intravenous Drug Formulations Containing the Preservative Chlorobutanol.

INTRODUCTION: Drug-induced torsades de pointes (TdP) is a potentially lethal ventricular arrhythmia that is associated with drugs that prolong the QT interval on the electrocardiogram (ECG) due to their interference with the cardiac potassium current, IKR. Intravenous (IV) formulations of methadone have been associated with TdP and contain the preservative chlorobutanol, which, like methadone, blocks IKR. The combinations of chlorobutanol with methadone or terfenadine, another IKR blocker, produce synergistic IKR block. OBJECTIVE: The aim of this study was to examine and summarize the evidence available to address the question: what other IV drug formulations contain chlorobutanol and are they associated with TdP? METHODS: IV drug products containing the preservative chlorobutanol were identified by searching the websites DailyMed ( https://dailymed.nlm.nih.gov/dailymed/index.cfm ) and Drugs@FDA ( https://www.accessdata.fda.gov/scripts/cder/daf/ ). For each drug identified, PubMed and the FDA's Adverse Event Reporting System (FAERS) were searched for reports of TdP and/or QT prolongation and FAERS data were analyzed for disproportionality of reports. RESULTS: The search found nine drugs (methadone, epinephrine, papaverine, oxytocin, vasopressin, testosterone, estradiol, isoniazid, and desmopressin) that contain chlorobutanol 2.5 (n = 1) or 5.0 mg/mL. All nine drugs had reports of QT prolongation or TdP reported in FAERS and all but estradiol, testosterone, desmopressin, and isoniazid had reports of QT prolongation or TdP in PubMed. Two of the nine drugs (epinephrine and methadone) had positive signals (by disproportionality analysis) for TdP in FAERS (EB05 2.88 and 23.81, respectively) and four (methadone, epinephrine, papaverine, and vasopressin) were reported in published articles as the suspect drugs in cases of TdP. CONCLUSION: The pharmacologic profile of chlorobutanol (synergistic IKR block) and its association with reports of TdP and QT prolongation suggest the need for a full evaluation of its cardiac safety when used as a preservative in IV drug and vitamin formulations.

Adverse Drug Event Causality Analysis (ADECA): A Process for Evaluating Evidence and Assigning Drugs to Risk Categories for Sudden Death.

Growing evidence indicates that many drugs have the ability to cause a potentially lethal cardiac arrhythmia, torsades de pointes (TdP). This necessitates the development of a compilation of drugs that have this potential toxicity. Such a list is helpful in identifying the etiology of TdP in patients taking multiple drugs and assists decision making by those caring for patients at high risk of TdP. The Arizona Center for Education and Research on Therapeutics (AZCERT) has developed a process to standardize the identification of drugs and place them in risk categories for their clinical ability to cause TdP and QT prolongation. AZCERT's Adverse Drug Event Causality Analysis (ADECA) utilizes 16 types of data drawn from four sources to compile an open-source knowledge base, QTdrugs, which is maintained on the CredibleMeds.org website. Because the evidence for most drugs is incomplete, the ADECA process is used to place drugs into one of three categories that represent different levels of certainty: known TdP risk, possible TdP risk, and conditional TdP risk. Each category has strict evidentiary requirements for clinical evidence of TdP and/or QT prolongation. These are described in this paper. Because evidence can evolve over time, the ADECA process includes the continuous gathering and analysis of newly emerging evidence to revise the lists. The QTdrugs lists have proven to be a valued, readily available, commercial influence-free resource for healthcare providers, patients, researchers, and authors of consensus guidelines for the safe use of medicines.