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Pharmacogenomics (Pharmacogenetics)

What is pharmacogenomics?

Pharmacogenomics is the study of how a person’s genes affect the way they respond to a medicine. This helps doctors know the best type of medicine or the correct dose of a drug to use for a person. Pharmacogenomics is also called pharmacogenetics.

For example, knowing about your child’s genes can tell the doctor:

  • Which medicine is likely to work best for your child’s illness
  • The best dose of a medicine for your child
  • How likely your child is to have a side effect from a medicine

How genes work

Genes are segments of DNA that act as a set of instructions and tell the body how to work. Every person’s genetic makeup is unique. Your genes are different from everyone else’s. Learning about your genes helps your doctors know how your body works.

Pharmacogenomic testing

Testing to learn how genes work with certain medicines is called pharmacogenomic testing. Doctors may order a pharmacogenomic test to find out which medicines and which doses are safe and most effective for your child.

Pharmacogenomic testing is often done through a blood test or a saliva test. Doctors can test genes in two general ways:

  • One gene at a time: This method is used when the doctor knows your child will need a certain medicine that is affected by that gene.
  • Many genes at a time: This method tests for several genes that can affect different medicines that your child might need. The pharmacogenomic test results will be in your child’s medical record for your doctor to use when needed.

Pharmacogenomic test results

Pharmacogenomic test results last a lifetime because genes do not change. Your child’s doctors and pharmacists can always use the results. This can help doctors pick the best medicines for your child in the future.

Save any pharmacogenomic test results you get. Tell your other doctors and pharmacists that pharmacogenomic testing has been performed and let them know the results. Pharmacogenomic test results will also be stored in your child’s medical record.

Your child could have more pharmacogenomic tests done in the future. Scientists are always finding new genes that affect how medicines and other treatments work, so there could be new genes to test for in the future.

Find more information

Learn more about how certain genes affect the medicines you take.

If you have questions about pharmacogenetic testing, talk to your care team. The availability of pharmacogenetic testing can vary by clinic or hospital.

For more information about pharmacogenomics at St. Jude, visit

See a list of common medicines.

Key Points

  • Pharmacogenomics, also called pharmacogenetics, is the study of how a person’s genes affect the way they respond to a medicine.
  • Pharmacogenomic testing helps doctors know the best type or dose of medicine to use for a person.
  • Your child may have a blood test to identify genes that affect medications.
  • Pharmacogenomic test results last a lifetime. They may be used now or in the future to pick the best medicines for your child.
  • Share the results of pharmacogenomic tests with your other doctors and pharmacists.

Reviewed: September 2022