Like many of my nurse colleagues, I became a nurse to care for patients and their families during times of need. Besides delivering care, I administered scheduled and as-needed drugs to patients, monitoring them for expected responses as well as possible adverse reactions. In a large majority of cases, prescribed medications worked as predicted. Occasionally, however, adverse reactions required interventions.
My nursing education, which began in the early 1980s, included the usual courses: fundamentals, obstetrics, pediatrics, medical-surgical, critical care, leadership, and, of course, pharmacology. In the pharmacology course, the focus was on specific drugs—their indications, typical side effects, and nursing interventions. This provided a strong foundation for my nursing career in critical care.
The nurse-pharmacology disconnect
My first position was in a cardiac surgical unit where patients recovered postoperatively from coronary artery bypass or valve replacement. After several years, I returned to school to complete my Master of Science in Nursing degree with an emphasis in critical care nursing and nursing education. I had courses in advanced physiology, advanced pathophysiology, nursing theory, nursing research, and nursing education. During this time, I began to teach in both clinical and academic settings. In the academic setting, I noticed that nurses were not teaching pharmacology courses, and I found this interesting in that administering medications is one of the important tasks a clinical nurse is responsible for overseeing.
In 1991, I was accepted into a doctoral program with an emphasis in cellular molecular pharmacology and physiology. This was a tremendous learning experience, and I developed, with regard to pharmacology, skills in cell culture and isolation—specifically endothelial cells—as well as molecular investigation of receptor activity. The only problem was that the model was based on an animal model—the guinea pig. And what does this all have to do with my patients?
The four rights of pharmacogenomics
During the summer of 2000, while I was attending the inaugural Summer Genetics Institute, sponsored by the National Institute of Nursing Research, the initial rough draft of the Human Genome Project (HGP)—a complete genetic sequencing of several men and women—was completed. The HGP has led to several important discoveries, and from it has come pharmacological matching of drugs with the genetic makeup of individuals. It’s called pharmacogenomics—the right drug for the right patient at the right dose and at the right time.
A broader perspective, or personalized medicine, is tailoring pharmacological treatment to a patient during all stages of care—prevention, diagnosis, treatment and follow-up—based on his or her individual characteristics, needs, and preferences. For me, all the pieces of the puzzle had come together.
Since that time, I have continued to teach about the genomic implications of pharmacology and what they mean to clinical as well as advanced practice nurses. I am excited that extensive pharmacogenomics work continues to be done. Since completing the Human Genome Project, the Federal Drug Administration (FDA) has identified more than 150 drugs for which there are molecular biomarkers that may aid in improving therapeutic outcomes and reducing adverse drug reactions. Thirty percent of these drugs and biomarkers are for oncology patients.
An exemplar comes from the cancer community. After a human epidermal growth factor receptor (HER2) biomarker was identified, which is resident in 30 percent of breast cancer and increases adverse outcomes, a humanized monoclonal antibody to HER2—trastuzumab, also known as Herceptin—was developed that targets the HER2 biomarker and reduces adverse outcomes.
A second exemplar comes from treating HIV/AIDS patients with antiviral agents—specifically, abacavir, either alone or in combination with another agent. Approximately 10 percent of patients receiving abacavir develop multiorgan hypersensitivity, and, for some, it’s fatal. Hypersensitivity to this drug has been associated with patients who are carriers for the allele HLA-B*5701, which can be identified with genetic testing. The FDA has issued a post-marketing recommendation that patients be tested before initiating or restarting the drug, either alone or in combination. This recommendation has also been added to the monograph insert.
A third exemplar is the prodrug clopidogrel, the antiplatelet agent used to reduce platelet aggregation in patients with acute coronary syndrome. When prescribed, this drug requires a functioning cytochrome 450 (CYP450) in the liver to convert the enzyme to an active metabolite. The specific enzyme is CYP2C19. In October 2013, the FDA approved a point-of-care device that enables a simple buccal swab to detect whether the patient has the normal or wild type, or the mutant version of the specific CYP2C19 enzyme. This will indicate if clopidogrel will be converted and protect the patient, or if the prodrug will not be converted and put the patient at further risk for clot formation.
This area of pharmacogenomics continues to expand. In 2015, the Obama administration announced the Precision Medicine Initiative. An emerging approach for disease treatment and prevention, it takes into account individual variability in genes, environment, and personal lifestyle. While significant advances in precision medicine have been made for select cancers, the practice is not currently in use for most diseases. Many efforts are underway to help make precision medicine the norm rather than the exception. The goal is to expand the base tenet of pharmacogenomics: the right patient and the right drug at the right dose.
Ask me about pharmacogenomics and precision medicine!
I get excited about communicating to nurses the importance of being informed about pharmacogenomics. They need to be educated about it and, more specifically, understand the Precision Medicine Initiative and how it applies to each patient. When fully instituted, no longer will drugs be ordered for the general patient on a trial-and-error basis. Instead, prescription of medications will be based on patient genotype and phenotype.
As patient advocates, nurses will need to be prepared to educate patients and families about genetic testing and how this information can be used to make decisions about pharmacological management. Nurses will be responsible for educating, informing, and discussing with patients, from a pharmacogenomics perspective, the best possible health outcomes and the role precision medicine will play in their overall treatment plan.
I am passionate for nurses to be informed about pharmacogenomics and precision medicine because they are responsible for providing quality care to patients, administering prescribed medications, and monitoring expected responses as well as potential adverse reactions. As nurses of today and the future, we are vital members of the entire health care team and will need to maintain pharmacogenomic competency to properly care for our patients.
Dennis J. Cheek, PhD, RN, FAHA, is the Abell-Hanger Professor in Gerontological Nursing at TexasChristian University-Harris College of Nursing and Health Sciences, with a joint appointmentin the School of Nurse Anesthesia.