Pharmacogenomics

What Is Pharmacogenomic Testing?

PGx testing looks at specific genes involved in how your body absorbs, metabolizes, and responds to certain medications. Some people break down a medication unusually quickly, which can mean a standard dose is less effective; others break it down unusually slowly, which can raise the risk of side effects at a standard dose. PGx testing can flag some of these differences ahead of time for certain, well-studied medications.

This is different from most genetic testing offered elsewhere on this site, which typically looks at disease risk. PGx testing doesn’t diagnose a condition or provide information about risk of future disease; it’s specifically about medication response.

Common Uses for PGx Testing

PGx testing is most established for certain medications in a few areas of care:

• Psychiatric medications, including some antidepressants, antipsychotics, and medications used to treat ADHD
• Cardiology, including certain blood thinners and medications used after procedures like stent placement
• Pain management, including some opioid and non-opioid pain medications. Guidelines exist for a smaller number of medications in this category than in psychiatry or cardiology, though the evidence base continues to grow.

This list isn’t exhaustive, and PGx research is an active, evolving area: new gene-drug relationships are still being studied and added to clinical guidelines.

If you’re specifically exploring the genetics of a psychiatric diagnosis, our Psychiatric Genetics page covers that in more depth.

What PGx Testing Can and Can’t Tell You

PGx testing can flag whether you’re likely to process certain medications faster or slower than average, and whether that’s associated with a higher chance of a medication not working well or causing side effects at standard doses. It’s one piece of information a prescriber can weigh alongside your medical history, other medications, and clinical judgment.

PGx testing can’t tell you which medication will definitely work for you, guarantee you won’t have side effects, or replace the trial-and-adjustment process that’s often part of finding the right medication or dose. A PGx result suggesting you likely metabolize medications at a typical rate doesn’t rule out all possible medication issues, since it only covers the specific genes and medications that have been studied.

A Note on Direct-to-Consumer PGx Results

Some direct-to-consumer (DTC) services now offer pharmacogenomic-style reports alongside ancestry or wellness results. These reports vary widely in what they test and how thoroughly they’re validated, and they aren’t a substitute for a clinically validated PGx test ordered through your care team. If you’ve received PGx-related results from a DTC test, a genetic counselor can help you understand what they do and don’t tell you, and whether further testing might be useful.

How Results Get Used by Prescribers

PGx results are typically interpreted using established clinical guidelines, most commonly from the Clinical Pharmacogenetics Implementation Consortium (CPIC), that translate a genetic result into a practical recommendation, such as a standard dose, an adjusted dose, or considering an alternative medication.

A genetic counselor can help you understand what your results mean, what questions are worth raising with your prescriber, and support that conversation so the information actually gets used in your care.

You might consider PGx-focused genetic counseling if you’re wondering:

• I’ve had pharmacogenomic testing done. What do these results actually mean for me?
• My doctor mentioned a gene test before starting or changing a medication. Should I do it?
• I’ve had trouble finding a medication that works for me. Could genetics be part of the reason?
• I got PGx results from a direct-to-consumer test. Are they something I should act on?
• I’m not sure if my situation fits, but I’d like to talk to someone about it.

What This Consult Doesn’t Replace

Genetic counseling is a valuable complement to your medical care, not a substitute for it. A genetic counseling consult does not replace an evaluation by your prescribing physician, such as your psychiatrist, cardiologist, or pain management provider, or their clinical judgment about your treatment. Decisions about starting, stopping, or adjusting a medication should always be made with your prescriber.

What genetic counseling can offer is a clearer picture of the genetic piece of that decision, one your prescriber can use alongside everything else they know about your care.