How many times has this happened to you? Your doctor prescribes a medication, you take the medication as prescribed, but the condition doesn’t improve. So, your doctor increases the dosage, but you still don’t feel any better, or you start having severe side effects.    

Would you be relieved to learn that you weren’t doing anything wrong? Instead, your genes may tell us how you were going to metabolize the medication in the first place. Enter pharmacogenomic testing.   

Personalized medicine
Pharmacogenomic testing entails examining a patient’s genes, via a blood sample or cheek swab, for any changes, or variants, that may be affecting the patient’s response to the medication.  

This testing, which has been performed at Cleveland Clinic for more than a decade, is a way of ”personalizing” medicine. For instance, if it is thought that a patient may need a higher dosage of a medication than someone else, pharmacogenomic testing can help make that determination.  

Testing for gene variants can help guide medication therapy. In fact, therapy can even be avoided if it is determined that a patient has a particular gene variant that causes them to metabolize medications more slowly or more quickly.  

The process is coordinated and communicated to patients by Pharmacy Clinical Specialists, such as Jennifer Hockings, PharmD, PhD, BCPS, Pharmacogenomics Clinical Specialist, Cleveland Clinic Department of Pharmacy. “I’m seeing patients to provide them information about pharmacogenomics,” she says. “We’re trying to evaluate if pharmacogenomic testing would be helpful for them, but also what the limitations are. Pharmacists are good at leading this, because we’re able to ask important questions, like, what are the drug-drug interactions? What’s the therapeutic window of this drug? And what are the alternatives?”    

What conditions and medications are tested?
At this time, pharmacogenomic testing is utilized for a limited number of conditions and medications, though the list is growing. At Cleveland Clinic, it is performed primarily for patients who have gastrointestinal conditions, such as Crohn’s disease and ulcerative colitis, for children who have cancer, and for patients taking antidepressants.   

Testing for antidepressants and antipsychotics is vital, according to Dr. Hockings. “We have a lot of patients who are being referred because they’ve tried multiple psychotropic medications and have not done well.”    

Pharmacogenomic testing also offers a forward-looking approach that Cleveland Clinic is taking that could benefit patients decades into the future. “For instance, when we’re testing a patient for antidepressants, in addition to those genes, we’re getting results that tell us that if you need a statin in the future, this particular statin might be a better choice than this other one,” Dr. Hockings notes.      

“So, if we have a 25-year-old patient who’s here for anxiety and depression, we can help them with their antidepressants. And then years down the road, if they need a statin, we would already have some information to help make the decisions on which statin to prescribe a little more precise or personalized.”    

A patient-centered approach
Gina Elder, PharmD, BCPS, BCGP, is a Geriatrics Clinical Pharmacy Specialist at Cleveland Clinic. In her role, she works with patients and providers to manage polypharmacy (when patients are taking several medications) and certain chronic diseases, such as dementia, anxiety, and depression. 

“I essentially tell patients ’I’m here to make sure that your medications are working for you and not against you,'” she says. “So, I look at all of their medications — prescription, over-the-counter and supplements — to make sure that they’re safe, effective and still necessary. And if we identify medication-related problems, then I’m collaborating with whoever prescribed them to see how we can best support that older adult with their medications.”   

Gina believes that pharmacogenomics testing has a place in the prescription and medication review process. “It has been useful as one piece of the puzzle to figure out what may be a good medication to treat things like anxiety and depression, where we know that a lot of folks don’t respond well to the first medication that we try,” she says. “Pharmacogenomics testing can provide some guidance.”   

Gina finds that her patients resonate with the idea of personalized medicine. “I do think people feel that it is very patient-centered when you’re saying, ‘we are looking at your DNA and this is what we’re doing about it.’ Because it’s your DNA. No one else has your DNA.”