Pharmacogenomics looks at the relationship between a person's unique genes and how it affects their response to medications. It involves genetic testing to identify variations within specific genes. Those genetic variations are used to assess the safety and effectiveness of medication for an individual, allowing for personalized drug therapy (also known as Precision Medicine). Precision medicine helps reduce drug toxicity, increases drug effectiveness, and improves overall health.
Here is an example of how different variations of the CYP2D6 gene affect the medication Paxil for treatment of depression or anxiety: