Introduction to Pharmacogenomics
More than six billion drugs are prescribed annually.
Many of these drugs do not work as intended, and over two million prescriptions in the U.S. result in an adverse reaction. While clinical trials on prescription drugs can determine data such as recommended dosages for the population involved, this approach assumes that all, or most, individuals share genomes that enable them to process drugs at a similar rate and in a similar manner. However, genetic variation can significantly impact individual responses to medications.
Pharmacogenomics is the study of drug-genome interactions and their clinical implications. This form of precision medicine looks for genetic markers that indicate how a resident might respond to a drug. These biomarkers are present on genes that encode for proteins that affect one or more aspects of how the body responds to the drug, including:
- Pharmacokinetic (PK) biomarkers: PK measures parameters involved in four different processes when a drug is administered: absorption, distribution, metabolism, and elimination.
- Pharmacodynamic (PD) biomarkers: PD is the study of how the drug affects the body, including factors such as receptor binding, chemical interactions, and receptor sensitivity.
- Human leukocyte antigen (HLA) biomarkers: HLA is an immune protein located on the surface of white blood cells. HLA can cause off-target binding that causes the immune system to overreact to certain drugs.
Because of differences in the way a resident’s body metabolize a specific drug compound, they may experience improper dosing, side effects, and drug-drug interactions that can be potentially dangerous. Due to the frailty of elders, this risk is even greater in long-term care environments.
Today, there are more than 450 medications whose use is improved by understanding a resident’s genetic makeup based on FDA drug labels. Moreover, the Clinical Pharmacogenetic Implementation Consortium publishes dosing guidelines for clinicians when genotype data is available.
To leverage this data, a simple DNA test can reveal how a resident’s body metabolizes a specific drug compound to inform the care team so it can customize treatment and calculate optimal dosing. The results can assist facilities in identifying, monitoring, and managing potential issues associated with resident medications.