How pharmacogenomics is changing medication decisions

The same medication can help one patient, cause side effects in another and have little effect in a third. That’s because more than 99% of people carry at least one genetic variant that can affect medication response, according to the . Pharmacogenomics (PGx) helps explain how a patient’s genes may affect medication metabolism and response.

WellSpan Health has been at the forefront of understanding the latest PGx insights and embedding new guidance into clinical workflows. We’ve made significant progress in three high-impact areas: cardiovascular care, oncology and psychotropic prescribing. In each, PGx guidance can help care teams identify patients who may face a higher risk of side effects, reduced medication benefit or severe toxicity before those problems affect patient outcomes.

Pharmacogenomics in practice at WellSpan Health

Cardiovascular care: Personalizing treatment for complex patients

For patients with cardiovascular disease, PGx insights can help identify when a medication may be less effective or more likely to cause side effects. About 30% of people have a genetic variant that makes clopidogrel (Plavix) less effective. These patients may remain at higher risk for blood clots, heart attacks, strokes and other cardiovascular events, even when taking their medication as prescribed.

Kate Cummins, PharmD

WellSpan Health has already implemented and is expanding PGx guidance for other cardiovascular medications, including beta-blockers, statins, hydralazine and mavacamten. For some patients, genetic variants can affect how slowly they metabolize these medications, increasing drug levels and raising the risk of side effects at standard doses.

“We’re making genetic information available in the prescribing workflow, where care teams can use it alongside everything else they already consider,” says Kate Cummins, PharmD, pharmacogenomics pharmacist at WellSpan Health. “That helps us tailor medication choices and dosing at key decision points, whether a patient is starting treatment, changing medications or experiencing side effects.”

These insights can help clinicians recognize when a standard medication or dose may not be the best fit, especially for patients with complex cardiovascular histories, medication side effects or specialty needs.

Cancer treatment: Reducing preventable harm

For some cancer patients, standard doses of certain chemotherapy drugs can cause potentially life-threatening toxicity, including severe diarrhea, mucositis and bone marrow suppression. PGx testing can help identify that risk early, giving oncology teams information they can use to plan safer treatment.

WellSpan Health has built genetic testing into treatment planning for certain chemotherapy medications. When a patient’s cancer treatment plan includes one of these medications, the patient can have testing as part of their pre-treatment workup.

“These mutations are rare, but if they go undetected, the side effects can be catastrophic,” says Pooja Sahni, MD, medical director of WellSpan Health’s medical oncology and hematology practice in Chambersburg. “Results come back quickly enough to make treatment decisions without delaying therapy. If a patient has a higher toxicity risk, we can adjust the dose or choose a different medication regimen before treatment begins.”

Psychotropic medications: Reducing trial and error

For patients taking psychotropic medications, finding a medication they can tolerate can take time. Patients with depression, anxiety, ADHD or other conditions may try several medications before finding one that helps them without causing difficult side effects, such as fatigue, weight gain, sexual problems or emotional blunting.

PGx testing can’t predict which psychotropic medication will work. But it can help explain how a patient metabolizes certain medications and whether they may be more likely to have side effects or need a different dosing approach.

WellSpan Health has built PGx guidance into prescribing workflows for psychotropic medications, including SSRIs, ADHD medications, anti-anxiety medications and antipsychotics. That gives prescribers practical information on medication metabolism, side effect risk and dosing, which they can weigh alongside patient history, symptoms and treatment response.

“When a medication is effective and not causing debilitating side effects, patients are more likely to stay on it,” says Lisa Gordon, MD, psychiatrist at WellSpan Health. “They’re more likely to have a better quality of life because the medication has been truly tailored to their needs.”

Building the foundation for future PGx-guided care

The Gene Health Project offers no-cost genomic sequencing to people age 18 and older through a cheek swab or blood sample. People can participate whether or not they receive care at WellSpan Health.

The project screens for CDC Tier 1 genetic conditions, not PGx results. Once a patient’s DNA is sequenced, a WellSpan Health provider can order PGx testing when medically indicated. Patients can also pursue testing, either proactively or when questions arise about a current or newly prescribed medication. This genetic information can support medication decisions throughout a patient’s care.

WellSpan Health is expanding clinical decision support at the point of prescribing in alignment with guidance from the Clinical Pharmacogenetics Implementation Consortium and the U.S. Food and Drug Administration. Pain management and rheumatology are among the next areas of focus.

For referring providers, WellSpan Health’s pharmacogenomics team can serve as a partner in evaluating a patient’s medication response, side effects or PGx-guided treatment planning.