
Pharmacogenetics is an area of genetic testing that assesses the genes responsible for the way a body handles and responds to medications.
A common pharmacogenetics application is related to drug metabolic pathways (how a body breaks down or metabolizes drugs). Mutations in these pathways affect an individual’s response to medication. Mutations in the genes of these pathways can cause a patient to be unable to break down a drug or to break down a drug too quickly or extensively; these mutations can make a drug ineffective or lead to an adverse drug reaction.
Indications for Testing
Pharmacogenetic testing is recommended to aid clinicians in determining the proper medication at the right dose to avoid adverse drug reactions and interactions. Pharmacogenetic test results become part of a patient's electronic health record and can be used for future medication prescribing.1 Pharmacogenetic testing should be offered to patients under the following circumstances:2- To provide pre-therapeutic guidance for drug and dose selection at:
- Psychiatric facilities
- Pain clinics
- Oncology centers
- Geriatrics
- To evaluate whether an adverse drug reaction (ADR), non-standard dose requirement, or therapeutic failure could be explained by known drug-gene associations.
- Patient has not received relief from his/her current prescription medication
- Patient has a family or personal history of unexpected outcomes from certain medications.
- Patient takes multiple prescriptions.
- Patient wants to be proactive and determine his/her phenotype (drug metabolism type) prior to taking a new medication.
Save Money
According to the U. S. Department of Health & Human Services, more than 770,000 injuries or deaths due to drug reactions occur in the United States each year. These events may cost a hospital up to $5.6 million each year. This number does not include the adverse drug events that cause hospital admissions, malpractice and litigation costs, or the cost of injuries to the patients.3
Pharmacogentic testing provides an opportunity to lower this number by:
- Preventing many adverse drug events before they occur.
- Reducing pharmacy costs for clients by optimizing dosage.
- Decreasing the number of patient hospitalizations.
- Improving patient compliance with their drug therapies.
- Pharmacogenetics test results become part of a patient’s medical record. The record can be referred to when future medications are prescribed.
1. Mayo Clinic, Center for Personalized Medicine. Pharmacogenomic PGx profile service.
2. PCLS. Personalized treatment through genes.
3. Agency for Healthcare Research and Quality. Reducing and preventing adverse drug events to decrease hospital costs.
Additional Report Information
The Cytochrome P450 Genotype Panel (ARUP test code 3001524 ) includes a link to a detailed enhanced report, supplied in conjunction with Coriell Life Sciences on their GeneDose LIVE site. The report is designed to assist clinicians in the interpretation and application of the genetic test results for their patient. The GeneDose LIVE report provides the genotype of the patient, and contains a medication summary with a list of medications that can be approached with standard precautions, those for which a dosage alteration or change in medication is recommended, and those for which an alternative is strongly suggested. The clinical evidence for each recommendation is marked as strong, moderate, or emerging.
Resources
Ordering recommendations in pharmacogenetics are currently based on specific drugs.
- PharmGkb Drug Labeling Order Recommendations Included with Drug Labeling
- U.S. Food and Drug Administration Table of Pharmacogenomic Biomarkers in Drug Labeling
- Clinical Pharmacogenetics Implementation Consortium (CPIC) Guidelines for Genotype-based Dosing
- Pharmacogenetics ARUP Consult
Testing recommendations are endorsed/promoted by professional societies in some cases.
- AIDS Info: National Institute of Health
Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents
Video Lecture with online credits: CME, SAM, PACE.
- Personalized Drug Therapy Is Here! An Update on Genetic Tools and Clinical Decision Support Available to Guide Drug and Dose Selection Today
Presented by Gwendolyn A. McMillin, PhD, DABCC(CC,TC) - Pharmacogenetics of CYP-Mediated Drug Metabolism
Presented by Gwendolyn A. McMillin, PhD, DABCC(CC,TC)