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What Is Pharmacogenomics?

Pharmacogenomics (also called “pharmacogenetics”) is the study of how our genes affect our response to some, but not all, medicines. Our genes, or DNA, provide the blueprint for our bodies and the things that make us unique. In some cases, doctors can use this genetic information to help pick which medicines or doses of medicines may be safer or work better for a person.

Pharmacogenomics is part of “precision medicine” (also called “personalized medicine” or “genomic medicine”). Precision medicine is a way for doctors to prevent, diagnose, and treat diseases based on things that make a person unique — like their age, gender, medical conditions, lifestyle, and genetic information.

How Does Pharmacogenomics Work?

Genes can affect how our bodies react to some medicines in different ways, such as:

  • How the body breaks down (metabolizes) and removes medicines. Not every person’s body breaks down medicines at the same rate. In some people, a medicine might break down too fast or too slow. If some medicines break down too quickly, the level of drug in a person’s body may be too low for it to work well. If some break down too slowly, the level of drug in the body could be too high and cause side effects.
  • How the body turns on (activates) medicines. The body needs to activate, or turn on, some medicines in order for them to work. If the body turns on too much active medicine, it can cause side effects. Or, a medicine might not work if the body doesn’t turn on enough of it.
  • How sensitive the body is to a medicine. Genes can make the body more sensitive or less sensitive to some medicines. A child whose body is less sensitive may need a higher dose of the medicine for it to work well.
  • How likely someone is to have a bad reaction to a medicine. Some genes can make a person more likely to have a rare but serious reaction to a medicine. If someone has one of these genes, doctors can choose a different medicine that is safer.

When Is Pharmacogenomic Testing Used?

Doctors might order pharmacogenomic testing before starting a new medicine or changing to a different one if a medicine didn’t work well or caused side effects. Labs can do pharmacogenomic testing with different types of samples, such as blood, saliva (spit), or a cheek swab. Ask your doctor or the lab which sample method is best for your child’s test. Depending on the lab, test results usually are ready in a few weeks, but may take a couple of months.

Doctors can use pharmacogenomics testing to choose medicines for:

What Do My Child’s Pharmacogenomic Results Mean?

The doctor will discuss your child’s pharmacogenomic test results with you. Depending on the results, the doctor might make changes to your child’s medicines. Do NOT stop or change any of your child’s medicines without talking to the doctor. Doing so could cause serious health problems.

Pharmacogenomic results do not change over time, so they can be used throughout a child’s life. In the future, experts may discover new genetic tests or uses, so your child’s testing could be updated later.

Genes and genetic test results aren’t the only information doctors use when making decisions about medicines. They consider other things that make a person unique, then come up with the best treatment plan.

If you have questions about the possible role of pharmacogenomics in your child’s care, talk to your doctor.

Date reviewed: January 2021