Pharmacogenetics: How Your Genes Affect Medication Response

When you take a pill, your body doesn’t just react the same way everyone else does. Your genes decide how fast you break down drugs, whether they’ll work at all, or if they might cause a dangerous reaction. This is pharmacogenetics, the study of how your inherited genes influence how your body responds to medications. Also known as personalized medicine, it’s not science fiction—it’s already changing how doctors prescribe drugs for depression, heart disease, and diabetes.

Take citalopram hydrobromide, an antidepressant that can build up to toxic levels in people with certain liver enzyme variants. Or empagliflozin, a diabetes drug that works better and safer in patients with specific genetic markers linked to kidney function. Even something as common as warfarin, a blood thinner, requires different doses based on just two genes. These aren’t rare cases—they’re the rule. If your body processes drugs too fast, the medicine won’t work. Too slow, and you risk overdose. Pharmacogenetics helps avoid trial-and-error prescribing, which often means weeks of feeling worse before finding the right fit.

Most people don’t realize that side effects like dizziness, nausea, or liver damage from meds aren’t always random. They’re often genetic. A test that checks your DNA for key drug-metabolizing enzymes can cut down on hospital visits and failed treatments. You won’t need to try five different antidepressants before one sticks. You won’t have to guess whether your high blood pressure drug will wreck your kidneys. Pharmacogenetics turns guesswork into guidance. The posts below show exactly how this plays out in real medications—from how pharmacogenetics affects pain control with calcitriol, to why some people respond to SGLT2 inhibitors while others don’t, and how genetic differences make one person’s asthma inhaler another’s nightmare. What works for your neighbor might not work for you—and now you know why.