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Will Pharmacogenetics Help Your Health?

By Pat Allen

Have you ever wondered why some medications work for others and not for you? Do you wonder why you have side effects to some medications, while your friend who takes the same medication has no side effects? Do you often pick up a prescription and pay a copay to find yourself back a few days or weeks later trying a different medication or different dose? Whether a medication will work for an individual depends on several factors – for example, how slow or how fast it metabolizes in your body. Another aspect is whether or not the prescribed medication is best matched to your genetic make-up.

In the United States, there are more than 100,000 deaths annually related to adverse drug effects. According to the Food and Drug Administration, over 700,000 Americans have serious consequences as the result of adverse drug reactions. An estimated 2 million hospitalizations occur yearly as the result. A long-standing approach of “one-size-fits- all” prescribing of medication not only does not work but puts individuals at risk for ADEs, drug toxicity and decreased drug efficacy. As many as 50 percent of medications prescribed are not taken or are stopped prematurely as the result of adverse effects. Many individuals simply stop taking their medication as a result of it failing to work. With respect to antidepressant medications, it’s estimated that medications are ineffective in as many as 38 percent of patients. It’s not uncommon for an individual to try three or four medications before finding one that works without intolerable side effects. The above does not take into account the added health care costs incurred, work lost or the impact on quality of life and family.

A rapidly growing answer to this problem is the use of pharmacogenetics testing. For the last decade, pharmacogenetics testing has emerged as a promising tool. Pharmacogenomics is the study of how genes affect a person’s response to medications both prescribed and over the counter. Pharmacogenetics is the study of genetic variations that influence an individual’s response to medications. Some individuals rapidly metabolize certain medication, while others poorly metabolize a drug. Understanding the way one’s genetic makeup impacts how the body responds to a drug moves the prescriber away from a trial-and-error method. Pharmacogenetic testing provides objective information about what drugs will work, those unlikely to work and those likely to cause side effects.

Pharmacogenetics testing simply entails a swab of the cheek. The sample is sealed, sent to the lab and analyzed. Results are available within two to three days. While there are similarities in vendor test reports, there are variations in the process, services and detail in the report. For example, turn-around time ranges from 24 to 72 hours from receipt of the sample. Support hours vary, with some vendors covering Monday through Friday only. The genetic testing is covered by most insurance companies, including Medicare and Medicaid.

There is exponential growth in the research supporting the value of PGT. The test includes three common panels. However, for the purposes of this article, the focus is on the neuro/psychiatric panel. This panel covers antidepressant, anti-anxiety, anti-psychotic, ADHD and pain. Pain includes neuropathic, migraine and arthritis. There are an increasing number of vendors providing the testing. There are common features of all vendor reports. Since more than 80 percent of medications process through the liver, testing analyzes several key drug-metabolizing enzymes from the cytochrome 450 family. Test results provide information about how fast and efficiently the body will respond to a medication. With respect to psychiatric medications, serotonin and norepinephrine transporter genes provide information about likely effectiveness of the drug. Additionally, the report includes catechol-O-methyltransferase, which relates to the ability to benefit from medications for attention deficit hyperactivity disorder. The modulation of emotion is impacted by COMT. This is very helpful not only with medication, but with lessening anxiety through non-pharmacologic modalities such as group therapy, meditation and yoga.

The report includes the influence of over-the-counter medications, as well as dietary influences, on prescribed medication. Both of these relate to drug-drug interactions. It is an objective tool to guide safe and efficacious prescribing. It guides the doctor or nurse practitioner in choosing the most safe and efficacious medication. It supports informed decision making by the individual. The physician or nurse practitioner meets with the individual to review the report and facilitates discussion about utilizing the results. This enables a partnership in care that empowers the individual. The partnership results in adherence to medication and reduction or resolution of symptoms.

Testing is both an intervention and preventative strategy. Pharmacogenetics testing is an integral part of personalized medicine. It replaces a long-standing trial-and-error approach with the help of science to create personalized medicine. Lastly, pharmacogenetic testing is a one-and-done endeavor. The information gleaned from the test can be used over a lifetime, making it beneficial and cost-effective.

Patricia Allen, MSN, PMHNP-BC, currently practices at Summit Behavioral Health in their PHP, IOP and outpatient services. She received her post-master’s Psychiatric Mental Health Nurse Practitioner at Drexel University, and is currently pursuing a Doctorate in Nursing Practice. Additionally, she practices in an acute behavioral hospital setting. Pat is tenured nursing faculty at Montgomery County Community College, in Blue Bell, Pennsylvania. She teaches mental health nursing and leadership. Several years ago she developed an elective mental health rotation for seniors interested in psychiatric nursing. Pat presented a poster on this endeavor at the annual American Psychiatric Nurses Association (APNA) in 2010 and 2012. She has developed case management programs for those with co-occurring disorders and presented her findings at the APNA and American Association of Occupational Health Nurses (AAOHN) conferences. Over the years she has served in various positions on the Philadelphia area board of directors of APNA, PSNA, CMSA and AAOHN.