RESUMO
OBJECTIVES: Assess the potential benefits of identifying drug-gene interactions in nursing home (NH) residents on multiple medications. Reduce the use of high-risk medications for residents with reduced drug metabolism. DESIGN: Open-label, nonrandomized, mixed methods study. SETTING: Four NHs in Ontario. MEASUREMENTS: Potential drug therapy problems (DTPs) for study cohort were identified during a medication review by a pharmacist using pharmacogenetic (PGx) clinical decision support to identify medication change opportunities. The number of DTPs identified during a standard medication review was compared with the number of DTPs identified with a PGx clinical decision support. Analysis of medication dispensing data at enrollment compared with dispensing in a 60-day window following medication review were compared for the PGx-tested study cohort with controls. RESULTS: Prescription patterns of 90 study participants were compared with 895 controls for the same time period. Study participants were on 7 to 47 drugs, of which drugs with PGx indications ranged from 1 to 17 medications. The average medication load was 4.6 medications with PGx indications per person, whereas the controls were on 3.5 PGx drugs. Furthermore, 94% of cases and 84% of controls were on 2 or more drugs with PGx indication during the study period. Pharmacogenetic analysis identified 114 distinct DTPs in the 90 study participants, of which 29 were classified as serious. In this study, over 35% of residents were treated with antidepressants; of these, 64% have altered CYP2C19 or CYP2D6 metabolism and could benefit from drug dose adjustment or from a switch to alternative antidepressants. Twenty percent of residents were treated with hydromorphone, of which 30% have reduced response to opioids because of variations in the OPRM1 gene. CONCLUSIONS AND IMPLICATIONS: This study demonstrated the clinical potential of PGx-based medication optimization for NH residents, impacting the management of depression, chronic pain, heart disease, and gastrointestinal symptoms.
