What Is Pharmacogenetics?

Pharmacogenetics, also known as pharmacogenomics, is the study of how an individual’s deoxyribonucleic acid, or DNA, affects the way they respond to different drugs. It is a combination of the study of drugs (pharmacology) and the study of genes (genomics).

Pharmacogenetics is part of precision medicine, which aims to tailor medical treatments to an individual or group of individuals rather than using “one size fits all” treatments. The results of pharmacogenetic tests can help medical professionals predict whether a certain medication will be effective for a specific individual and if any adverse effects will occur.

How does pharmacogenetics work?

Researchers of pharmacogenetics use information from the Human Genome Project to learn how genetic differences affect the body’s response to medication. An individual’s DNA affects the number and type of medication receptors in the body, the speed in which a medication is absorbed and removed from the cells, and how quickly the body breaks down a medication. Pharmacogenetics uses these factors to identify what types and dosages of medication will provide the best response in an individual.

In addition to being used for treatment decisions, pharmacogenetics can also be used to develop medications to treat diseases caused by genetic mutations. Certain mutations can lead to absent or malfunctioning proteins in the body. Pharmacogenetics can help develop medications to address a mutation’s effect on specific proteins. An example is the medication ivacaftor, which can be prescribed for a mutation that causes cystic fibrosis.

What health conditions may benefit from pharmacogenomics?

A variety of medical conditions may benefit from pharmacogenetic-based treatments, including, but not limited to, the following:

• Breast cancer
• Epilepsy
• High cholesterol
• HIV
• Certain autoimmune diseases

What medications are influenced by genetics?

Examples of medications that may be influenced by genetics include the following:

• Statins for the treatment of high cholesterol
• Ado-trastuzumab emtansine for the treatment of breast cancer
• Amitriptyline for the treatment of depression
• Clopidogrel for antiplatelet therapy
• Allopurinol for the treatment of gout
• Azathioprine for immunosuppression

A health care provider may suggest pharmacogenetic testing for an individual if a medication is not working or causing side effects. Pharmacogenetic testing may also be recommended before a new medication is prescribed. The tests are conducted by collecting DNA, either through a blood test, a cheek swab, or saliva collection.