Doctor gesturing to prescription bottle while talking with patient in office

Pharmacogenomics for Patients

Have you ever wondered why some medications may not seem to help you as much as others?

Have you ever changed the dose or stopped taking a medication because you didn't think it worked for you or didn't like the way it made you feel?

Have you ever wanted to know how a medication may affect you before you take it?

These types of questions might be answered by pharmacogenomics (PGx), which is the study of how genes affect the body's response to medications. Emerging tools for PGx testing, also referred to as drug-gene testing, can guide your doctor to tailor your medications based on your genes. This is key to personalizing your health care.

What is PGx?

PGx is the study of how your genes may affect your body's response to, and interaction with, some prescription or over-the-counter medications.

Genes, which are inherited from your parents, carry information that determines characteristics such as eye color and blood type. Genes can also influence how you process and respond to medications.

Depending on your genetic makeup, some medications may work faster or slower, or produce more or fewer side effects.

Why is PGx important?

The results help tailor your medication based on your genes now and for future prescription needs.

What pharmacogenomic testing does

The purpose of pharmacogenomic testing is to find out if a medication is right for you. A small blood or saliva sample can help determine:

  • Whether a medication may be an effective treatment for you
  • What the best dose of a medication is for you
  • Whether you could have serious side effects from a medication

The laboratory looks for changes or variants in one or more genes that can affect your response to certain medications.

Although your genetic makeup does not change over time, it may be helpful to talk to your health care provider about having a pharmacogenomics test repeated in several years as the science and technology advances. You may need other pharmacogenomic tests if you take another medication, but laboratories can perform multiple tests from a single blood or saliva sample. Each medication is associated with a different pharmacogenomic test. Keep track of all your test results and share them with your doctor.

The need for pharmacogenomic testing is determined on an individual basis. If your pharmacogenomic test results suggest you may not have a good response to a medication, your family members may have a similar response. Mayo Clinic recommends you share this information with your family members. Your doctor can also provide recommendations for family members who may benefit from having testing.

What factors impact response to medications?

PGx testing is one tool your health care team can use to help identify the right drug for you. Many factors impact how a person responds to medication including:

  • Genetic factors
  • Other medications
  • Age
  • Sex
  • Race/ethnicity
  • Illness or organ dysfunction, especially of the kidney or liver
  • Smoking/alcohol
  • Food interactions
  • Weight-loss surgeries

When might PGx testing be recommended or considered?

There are different reasons why your health care team might order PGx testing to help guide your current or future medication use, such as:

  • To reduce the risk of serious side effects related to certain medications
  • To adjust the dose of a current medication or recommend a different medication
  • To identify a medication, or dose of a medication, with a higher chance of working for you before you take it

How much will it cost?

The cost varies depending on which test(s) is ordered. Depending on your policy and reasons for testing, some insurance companies may or may not cover pharmacogenomic testing.

Contact your insurance provider about coverage prior to testing if this is a concern. To help you determine test costs and coverage:

  • Mayo Clinic's Patient Account Services may be able to provide an estimate by phone.
  • Some insurance companies may cover pharmacogenomic testing, depending on the policy and reasons for testing.
  • Contact your insurance provider about coverage prior to testing if cost and coverage are concerns.

In addition to PGx testing costs, you will incur charges related to the visit with your doctor, and those charges may vary.

Will PGx testing affect insurance coverage?

GINA, the Genetic Information Nondiscrimination Act, prohibits medical insurance companies and employers from discriminating against individuals on the basis of genetic information, including PGx test results. This federal law does not protect you against genetic discrimination by life insurance, disability insurance or long-term care insurance companies. Some states have laws in this area. Learn more on the National Institutes of Health's Genetic Discrimination webpage.

Pharmacogenomics: Genes and Drugs

Richard Weinshilboum, M.D.

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Pharmacogenomics Animation

Pharmacogenomics investigates how variations in genes affect response to medications, using a patient's genetic profile to predict a drug's efficacy, guide dosage and improve patient safety.