Pharmacogenomics is a hot topic that more and more people are talking about. Judging from the name alone, it can be deduced that it has something to do with both pharmacy and genetics. What exactly is the impact it could make towards personalization and precision medicine, and what is so special about it? Let’s delve into this topic and find out.

What is Pharmacogenomics?

Pharmacogenomics is essentially the study of how a person’s genetic makeup determines how they will respond to medications.¹ It’s linked to the field of precision medicine that focuses on each patient individually.

Its potential lies in the ability to use a person’s genetic information that is uniquely theirs to predict the response they will have to any drug while continuing to further optimize even dose selections once the drugs have been carefully selected.³ The end goal is fully personalized treatment that is cost-effective, safe, and improves health outcomes for the individual and to know whether or not the medication will work ahead of time.

As pharmacogenomic testing becomes more widely available, healthcare systems are increasingly incorporating genetic information into routine patient care. Clinical organizations such as the Clinical Pharmacogenetics Implementation Consortium (CPIC) now provide evidence-based guidelines that help healthcare professionals translate genetic test results into medication-related decisions.

Genes and Medication

Our genes affect the way our body responds to a drug. Drugs interact with our body in multiple ways, and certain proteins or enzymes present in our body affect how these drugs will work. Pharmacogenomics analyzes the variations among our genes to find these proteins and what effect they will have on the drug’s safety and effectiveness in the body.¹ Pharmacogenomic testing can identify specific genetic variants that influence drug metabolism, transport, and receptor activity, helping clinicians better predict medication response.

Examples of how our genes can affect how we respond to a drug:²
1) Drug Receptors on Cell Surfaces
○ What type and how many receptors we have
○ Affects the intensity of response or no response to a drug
2) Drug Uptake into Tissues and Cells
○ How well the drug is taken up into tissues and cells (normal=drug works as expected and/or should)
○ Less uptake means the drug isn’t working as well as it should and may accumulate and cause problems
○ Increased uptake could cause adverse effects
3) Drug Breakdown by Enzymes
○ How quickly the body breaks down and gets rid of a drug
○ Might need less of a drug if the body breaks it down slowly
○ Might need more of a drug if the body breaks it down quickly

Pharmacogenomics by the Numbers

Pharmacogenomics continues to gain momentum in healthcare as more evidence supports its role in medication optimization.

• More than 99% of individuals are estimated to carry at least one actionable pharmacogenomic variant that may influence medication response.
• A recent survey identified 43 healthcare institutions actively offering pharmacogenomic testing services.
• Approximately 74% of those institutions reported obtaining formal informed consent before pharmacogenomic testing.
• The FDA continues to expand pharmacogenomic information included in medication labeling to support safer and more effective prescribing decisions.

The Benefits and Drawbacks

The Food and Drug Administration (FDA) includes pharmacogenomic information on the labels of hundreds of medications. This information assists healthcare professionals when prescribing drugs by providing guidance related to dosing, safety, effectiveness, and genetic factors that may influence treatment outcomes. Medications with pharmacogenomic considerations include warfarin, clopidogrel, escitalopram, codeine, sertraline, amitriptyline, tacrolimus, carbamazepine, allopurinol, and abacavir, to name a few. More examples can be found here.

Drug companies are using pharmacogenomics for developing and marketing drugs in use for patients with certain genetic variants for maximum therapeutic benefit. In addition, once gene variants are identified in patients, doctors are then able to select the appropriate and optimal medication along with the dose for that specific patient. Moreover, if these genes were to cause side effects from a certain drug, that drug can be avoided and prescribed only to those who don’t have those genes.

In addition, organizations such as the Clinical Pharmacogenetics Implementation Consortium (CPIC) and the Dutch Pharmacogenetics Working Group (DPWG) continue to publish evidence-based recommendations that help healthcare professionals apply pharmacogenomic information in clinical practice.

There are potential advantages to using pharmacogenomics such as optimized drug selection, improved treatment outcomes, enhanced safety, avoidance of trial and error approach when it comes to selecting a medication, and improved cost effectiveness due to not having to try multiple medications and/or treatments.

Reimbursement and Coverage Trends

One of the historical barriers to widespread pharmacogenomic implementation has been insurance coverage. Today, several Medicare Administrative Contractors provide coverage pathways for certain pharmacogenomic tests when medical necessity criteria are met. Commercial insurance coverage continues to evolve, although reimbursement may vary depending on the test performed, medication involved, and clinical situation.

As evidence supporting pharmacogenomic-guided therapy continues to grow, healthcare systems and payers are increasingly recognizing its potential value in improving outcomes and reducing medication-related complications.

However, that’s not to say it’s all a flawless process. There are certain ethical and legal factors to be considered when it comes to pharmacogenomics. A patient’s autonomy along with their right to privacy are serious matters of consideration. Potential bias and discrimination could also occur through underrepresentation of certain groups in the data, or by making clinical decisions based on the data but failing to consider individual patient factors. Taking the proper steps to obtain informed consent and maintain patient confidentiality are key.

Additionally, healthcare professionals must ensure that pharmacogenomic information is used appropriately and that treatment decisions continue to consider the whole patient, including medical history, concurrent medications, and treatment goals.

The Takeaway

Understanding pharmacogenomics can improve treatment methods and selection down the line, especially when they’re tailored to a patient’s own unique genetic profile. The field is still growing, but it’s growing quickly and there is still much to embrace in terms of knowledge, evidence, and implementation. Yet, with this personalized approach, healthcare providers such as pharmacists are at the forefront of delivering treatment that may be safer, more effective, and individualized for each patient. Pharmacists increasingly help interpret pharmacogenomic test results, identify gene-drug interactions, educate patients, recommend therapy modifications, and collaborate with prescribers to optimize medication outcomes.

Original Author: Midrara Kashmari

Editorial Update (June 2026): Elizabeth Rodriguez

RxPharmacist Team

References:

1. National Institute of General Medical Sciences (NIGMS). National Institute of General Medical Sciences (NIGMS). Published 2022. https://nigms.nih.gov/education/fact-sheets/Pages/pharmacogenomics.aspx#:~:text=Pharmacogenomics%20(sometimes%20called%20pharmacogenetics)%20is.
2. Centers for Disease Control and Prevention. Pharmacogenomics: What does it mean for your health? CDC. Published 2019. https://www.cdc.gov/genomics/disease/pharma.htm.
3. Krebs K, Milani L. Translating pharmacogenomics into clinical decisions: do not let the perfect be the enemy of the good. Human Genomics. 2019;13(1). doi:https://doi.org/10.1186/s40246-019-0229-z.
4. U.S. Food and Drug Administration. Table of Pharmacogenomic Biomarkers in Drug Labeling. Available at: https://www.fda.gov/drugs/science-and-research-drugs/table-pharmacogenomic-biomarkers-drug-labeling
5. Clinical Pharmacogenetics Implementation Consortium (CPIC). Available at: https://cpicpgx.org
6. Chanfreau-Coffinier C, et al. Projected prevalence of actionable pharmacogenetic variants among Veterans Health Administration pharmacy users. JAMA Network Open. 2019.
7. Mills R, Haga SB, et al. Assessment of the current status of real-world pharmacogenomic testing. Frontiers in Pharmacology. 2024.