Advancing Precision Therapeutics in Older Adults: A Scoping Review of Pharmacogenomic Service Models

Older adults remain a therapeutically understudied population despite experiencing the highest burden of polypharmacy, age-related pharmacokinetic and pharmacodynamic variability, and medication-related harm. Pharmacogenomic testing offers an opportunity to individualize drug therapy in this population; however, its clinical implementation is complicated by population-specific challenges. We conducted a scoping review to describe existing pharmacogenomic testing services implemented in adults aged ≥ 65 years and to identify design features that support translation of genomic information into therapeutic decision making. Five databases were searched from inception to May 2026. Studies were included if pharmacogenomic test results were used to inform prescribing decisions. Data were extracted on pre-implementation actions, implementation workflows and types of outcomes assessed. The review was conducted in accordance with the PRISMA guidelines. Eleven pharmacogenomic services were identified, implemented across diverse settings including primary care, geriatric clinics, residential aged care, pharmacies, and telepharmacies. Multiple design elements were deduced to support therapeutic integration of pharmacogenomic testing: (1) leveraging medication management workflows, (2) delivering pre-implementation healthcare professional education, (3) targeting population-relevant gene and allele panels, (4) establishing simplified organizational guidelines, (5) utilizing clinical decision support tools to identify drug-gene and drug-drug-gene interactions, (6) pharmacist-led interpretation of results, and (7) iterative service evaluation. Notably, most services were embedded within broader medication management programs, positioning pharmacogenomic testing as a tool to refine, rather than replace, existing therapeutic decision making in older adults. The findings provide a pragmatic framework for designing pharmacogenomic services that advance precision therapeutics in older adults and highlight priorities for future implementation and evaluation.