Pharmacogenomics
A new way to personalize the journey of finding the right medication based on genetics
By Eileen Levesque
Whether you are new to or are experienced in dealing with mental health challenges, the process of finding an effective treatment can be puzzling, dynamic, and often a very time-consuming enterprise. You may talk about your challenges with friends and family who have experienced similar afflictions. They may share with you the names of medications that helped them feel healthy again, but no two people are the same and medications are not a “one-size-fits-all” solution. From a genetic standpoint, we are more alike than one may think. We humans share over 99% identical genetic information. However, that remaining small percentage of variation is what makes us unique in ways such as personality, appearance, disease risk as well as how we respond to drugs in our body.
As a pharmacist, I’ve always known that a medication can work well for one person, but may be toxic to the next person (even at the same dose), and just completely ineffective to yet a third person. Certainly, there are tools that prescribers have used for years to predict drug response, such as age, height, weight, kidney or liver function, etc. But innovation has provided major advances in drug response predictability. The Human Genome Project was completed in 2003. From this project, medical professionals have garnered a wealth of new information and we are now able to optimize patient outcomes as we expand our understanding of how best to work with a patient’s own genetic make-up. Examining an individual’s genetic variations can help clinicians tell, in advance, if a patient is likely to experience drug build-up in their body (due to slow metabolism of drug), low levels of drug in the body (due to faster metabolism of the drug), as well as the likelihood of allergic reaction. This science, called Pharmacogenomics or PGx for short, has added precision to the process of drug selection and there is established guidance for over 300 drugs, thus far.
Contrary to popular belief, most people who are newly experiencing mental health challenges do not immediately seek relief through medication therapy. Women are particularly prone to waiting it out. While time and alternative therapies can be helpful in many cases, still too many of us wait an extended time to seek medical attention. A recent nationwide survey from Myriad Genetics, Inc released in April 2022 showed 51% of women diagnosed with anxiety and/or depression waited at least a year to seek medical attention, and many never even pursued treatment. This impacts wellness over the long term. When we have reached the end of our own attempts to make things better and have come to the realization that we may need prescription medication, there is often still a long road ahead to find the right medication which is effective without burdensome side effects. Most medications prescribed for depression and anxiety today require a four to six-week trial before the drug is deemed a success or failure. (Of course, if side effects limit the tolerability, your doctor may stop the medication sooner.) Then, on to the next drug trial for another four to six weeks! Time progresses, and it often may take months (sometimes years) of clinical trial and error before the right medication is found. A patient’s relationships, livelihood, and quality of life in general may deteriorate during that time. This prescription odyssey can often be shortened when PGx tests are used to help rule out medications unlikely to work for a patient, or likely to build up in the body and cause unpleasant side effects.
This is not to say that PGx testing guarantees the first medication you try will be “the one.” As mentioned, there are many other factors that may affect drug breakdown or accumulation in the body such as height, weight, kidney/liver function, smoking, alcohol consumption, age, etc. However, PGx is quickly emerging as a vital tool to help pharmacists and physicians predict medication outcomes more accurately by predicting drug metabolism, decreasing the risk of serious side effects, and reducing trial and error prescribing. There are currently guidelines established for predicting drug-gene interactions in the clinical areas of psychiatry, oncology, cardiovascular disease, gastrointestinal disease, diabetes, ADHD, and pain management. The guidelines are written and updated by the Clinical Pharmacogenomics Implementation Consortium (CPIC), managed by Stanford University and St. Jude Children’s Research Hospital.
As pharmacogenomic studies continue to increase clinical evidence and the cost of testing continues to decrease, expect this innovative approach to become ever more mainstream, and ideally proactive (before a medication is prescribed). Until then consider exploring PGx testing if you or a loved one are struggling to find the right medication because time spent feeling healthy is priceless.
For more information, visit bespokehealthpartners.com