Many drugs that are currently available are “one size fits all,” but they don’t work the same way for everyone. It can be difficult to predict who will benefit from a medication, who will not respond at all, and who will experience negative side effects (called adverse drug reactions). Adverse drug reactions are a significant cause of hospitalizations and deaths in the United States. With the knowledge gained from the Human Genome Project, researchers are learning how inherited differences in genes affect the body’s response to medications. These genetic differences will be used to predict whether a medication will be effective for a particular person and to help prevent adverse drug reactions.

The field of pharmacogenomics is still in its infancy. Its use is currently quite limited, but new approaches are under study in clinical trials. In the future, pharmacogenomics will allow the development of tailored drugs to treat a wide range of health problems, including cardiovascular disease, Alzheimer disease, cancer, HIV/AIDS, and asthma.

What Pharmacogenomics 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.

Each person would need to have the same specific pharmacogenomic test only once because your genetic makeup does not change over time. However, you may need other pharmacogenomics tests if you take another medication. Each medication is associated with a different pharmacogenomics test. Keep track of all your test results and share them with your health care providers.

The need for pharmacogenomics 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 health care provider can also provide recommendations for family members who may benefit from having testing.