11/11/2026
A University of Pittsburgh-led analysis of nearly 100,000 people found that gene variants affecting medications are universal, not rare.
PITTSBURGH — Nearly 100,000 people who had their genomes studied through the National Institutes of Health's All of Us Research Program all carried at least one gene variant known to affect how their body processes medications, according to a University of Pittsburgh-led study published Nov. 11, 2026, in Science Translational Medicine.Key Takeaways
- A Pitt-led analysis of nearly 100,000 participants in the NIH All of Us Research Program found that everyone carried at least one genetic variant known to affect how the body processes medications, with a median of nine variants per person.
- The study, published in Science Translational Medicine, found 24.4% of participants had been prescribed a medication known to interact with a genetic variant they carried, most commonly ondansetron, ibuprofen, omeprazole, pantoprazole and atorvastatin.
- Senior author Philip E. Empey, Pharm.D., Ph.D., of Pitt's School of Pharmacy, said the findings support wider use of genetic testing and electronic health record alerts to guide prescribing decisions.
- First author Andrew Haddad, Pitt School of Pharmacy Ph.D. student, led the research as part of his dissertation work in Empey’s laboratory.
- The research team identified more than 17,000 novel genetic variants and reported variant frequencies across multiple ancestry groups, including populations not previously studied.
The most common medications identified were ondansetron, an anti-nausea drug; ibuprofen, an anti-inflammatory; omeprazole and pantoprazole, both used for acid reflux and heartburn; and atorvastatin, a cholesterol-lowering drug. More than 300 medications carry label information about gene-drug interactions where testing may guide prescribing, Empey said. One example is a chemotherapy drug used for colon cancer that can cause serious toxicity in up to 8% of patients who carry certain variants, so those patients are tested before treatment begins.
Nationwide Genetic Data From the All of Us Research Program
The research team analyzed variants in 16 genes known to affect how well medications work or how safe they are. Every participant carried at least one of these variants. The median number of variants per person was nine.
Pitt has been a partner in the All of Us Research Program since launching All of Us Pennsylvania in 2018. The program gathers genetic, health record and lifestyle data from people across the country.
"Many people have experience with taking a medication that is not working well for them or that has a side effect," said senior author Philip E. Empey, Pharm.D., Ph.D., associate professor in Pitt's School of Pharmacy and associate director for pharmacogenomics at the Institute for Precision Medicine at Pitt and UPMC. "While many things impact how a patient responds to medication, our research tells us that genetics could be factor for a large proportion of patients and it points to the value of precision medicine in prescribing."
Novel Variant Discovery Expands Genetic Diversity Data
The team identified more than 17,000 variants not previously documented. Researchers also reported the frequency of known medication-linked variants across multiple ancestry groups, including populations where these frequencies had not previously been estimated.
"The limited diversity of racial and ethnic groups in early studies is a challenge in genetic research and skews risk estimates," Empey said. "That's part of the beauty of the All of Us Research Program – it was intentionally designed to help close these gaps by including people from a wide range of age groups, backgrounds and life experiences. It also underscores the value of having a large precision medicine dataset where whole genome testing data can be studied along with clinical data."
Bringing Gene-Based Prescribing Into Everyday Clinical Care
Empey said it will be up to policy makers and health insurers to weigh the benefits of widespread genetic testing against its cost. He said it makes sense to screen patients with a panel test that checks for variants known to affect many medications and store the results in a patient's medical record, similar to a kidney function test. This approach is also being applied when patients take many medications at once, or when they start medications such as clopidogrel, used after cardiac stenting, that are known to be affected by genetics.
People who have already had this type of testing, called pharmacogenomic testing, should share their results with their pharmacists and prescribers so the information is added to their electronic health record, Empey said. He is leading efforts at UPMC to make it easier for clinicians to see whether a patient carries variants that may affect a medication being prescribed and to recommend changes when needed.
"Just like with any new technology, it comes down to responsible implementation," Empey said. "Costs are coming down and the data is increasing, so it is important for patients and clinicians to be aware that the use of precision medicine in prescribing is becoming commonplace."
Frequently Asked Questions
Q: What is pharmacogenomic testing and how common are gene variants that affect medications?
A: Pharmacogenomic testing checks a person's DNA for variants that affect how they respond to medications. In this study, every one of nearly 100,000 participants carried at least one such variant, with a median of nine variants per person.
Q: Which medications were most commonly affected by these gene variants in the study?
A: The most common were ondansetron (anti-nausea), ibuprofen (anti-inflammatory), omeprazole and pantoprazole (both treat acid reflux and heartburn), and atorvastatin (lowers cholesterol).
Q: Should I get genetic testing before taking a new medication?
A: Testing may be useful for certain medications where gene-drug interactions are well established, such as some chemotherapy drugs and clopidogrel. Patients who have already had testing should share results with their pharmacist and prescriber.
Additional Resources
- Published study: Frequency of pharmacogenomic variation and medication exposures among All of Us Participants | Science Translational Medicine
- Press release: Could your genes affect your medications? New study highlights high probability | EurekAlert!
- Press contact: Allison Hydzik and Elaine Vitone
- National Institutes of Health All of Us Research Program
- Institution for Precision Medicine at Pitt and UPMC
- Pittsburgh Pharmacogenomics
- Pitt Pharmacy to lead new Pharmacogenomics Center of Excellence
- UPMC Uses Gene Test to ‘Personalize’ Meds for Heart Patients
- Genetic Testing for Medicines | UPMC Health Library
Authors and Funding
Authors: Andrew Haddad, Pharm.D., Ph.D., and Kathleen Polkowski, Pharm.D., M.B.A., both of Pitt; Aparna Radhakrishnan, Ph.D., Sean McGee, Ph.D., Joshua D. Smith, Ph.D., Marsha M. Wheeler, Ph.D., Karynne Patterson, and Gail P. Jarvik, M.D., Ph.D., all of the University of Washington; Jason H. Karnes, Pharm.D., Ph.D., of the University of Arizona; Eric Venner, Ph.D., Kimberly Walker, M.S., Divya Kalra, M.S., Sara E. Kalla, Ph.D., Qiaoyan Wang, M.A., and Richard A. Gibbs, Ph.D., all of the Baylor College of Medicine; and Janeth Sanchez, Ph.D., M.P.H., Anjené Musick, Ph.D., M.P.H., Andrea Ramirez, M.D., M.S., and Joshua C. Denny, M.D., M.S., on behalf of the All of Us Research Program.
Funding and Disclosures: This research was funded by the NIH (grants listed in the Science Translational Medicine manuscript), Shear Family Foundation and Myers Family Foundation.
