The American Society of Health-System Pharmacists (ASHP) believes that pharmacogenomic testing can improve medication-related outcomes across the continuum of care in all health-system practice settings. These improvements include reduction in suboptimal clinical outcomes, decreased cost of treatment, better medication adherence, more appropriate selection of therapeutic agents, decreased length of treatment, and enhanced patient safety.1–3 Because of their distinct knowledge, skills, and abilities, pharmacists are uniquely positioned to lead inter-professional efforts to develop processes for ordering pharmacogenomic tests and for reporting and interpreting test results. They are also uniquely qualified to lead efforts to guide optimal drug selection and drug dosing based on those results. Pharmacists therefore have a fundamental responsibility to ensure that pharmacogenomic testing is performed when needed and that the results are used to optimize medication therapy.1 Pursuant to this leadership role, pharmacists share accountability with other hospital and health-system leaders, such as physicians, laboratory professionals, and genetic counselors, for the ongoing implementation and application of pharmacogenomics across the continuum of care. Because test results will have implications throughout a patient’s lifetime, all pharmacists should have a basic understanding of pharmacogenomics in order to provide appropriate patient-care recommendations. Some advanced pharmacist functions in applying clinical pharmacogenomics may require specialized education, training, or experience. ASHP encourages pharmacist education on the use of pharmacogenomics and advocates inclusion of pharmacogenomics and its application to the therapeutic decision-making process in college of pharmacy curricula and Board of Pharmacy Specialties certification programs.
Clinical pharmacogenomics uses genetic information to guide optimal drug selection and drug dosing for patients to maximize therapeutic effects, improve outcomes, and minimize toxicity.2 Pharmacogenomic testing can be performed reactively or preemptively. Reactive testing generally occurs when a patient is experiencing adverse effects unexplained by dose or drug-drug or drug-disease interactions, or when the use of a high-risk drug is anticipated and the patient’s genotype is obtained in anticipation of starting therapy. In contrast, preemptive testing occurs when patients are screened for multiple pharmacogenomic variants prior to developing an indication for specific pharmacotherapy.
Application of pharmacogenomic information requires an understanding of how genetic variations impact the pharmacokinetic and pharmacodynamic properties of a drug in specific diseases and patient populations, as well as understanding molecular pathways. The influence of factors such as age, sex, diet, pathophysiologic conditions, and current medication use, as well as their relationship to genetic variability must also be understood. As awareness of individual genetic variation grows due to improved access to lower-cost testing and availability of evidence-based consensus guidelines in pharmacogenomics,4 the development of patient-individualized therapeutic regimens should include an assessment of patients’ pharmacogenomic profiles in addition to allergy and adverse reaction history, drug interactions, dietary and lifestyle factors, patterns of adherence, and other therapeutic drug-monitoring parameters.5 The FDA provides a list of drugs for which pharmacogenomic markers are included in the drug labeling,6 and the Clinical Pharmacogenetics Implementation Consortium (CPIC) has published ASHP-endorsed therapeutic guidelines for multiple drug-gene pairs.7,8
The pharmacist’s patient-care functions include appropriate and cost-conscious medication selection and monitoring, which now increasingly includes pharmacogenomic profile assessment. The purpose of this statement is to describe pharmacists’ responsibilities and accountabilities in the field of pharmacogenomics.
Pharmacists’ responsibilities for pharmacogenomics include promoting the optimal use and timing of pharmacogenomic tests; interpreting clinical pharmacogenomic test results; and educating other pharmacists, fellow health care professionals, patients, and the public about the field of pharmacogenomics. The following are responsibilities that should be part of any clinical pharmacogenomics service: