Pharmacological Interactions Between Nutritional Supplements and Prescription Medications in Older Adults: A Comprehensive Review.

The global aging population faces increasing risks of supplement-drug interactions due to rising polypharmacy and widespread use of nutritional supplements. Older adults, particularly those with chronic conditions, frequently combine prescription medications with dietary supplements, yet healthcare providers often overlook these interactions, leading to preventable adverse effects. This review synthesizes evidence from 16 international studies spanning nearly three decades, examining the intersection of supplement and medication use in older adults. Key findings reveal a high prevalence of concurrent use (23-82.5%), significantly increasing the likelihood of adverse interactions, particularly with antithrombotics (e.g., warfarin and ginkgo) and absorption-disrupting minerals (e.g., calcium and levothyroxine). A critical systemic failure in patient-provider communication exacerbates these risks, as clinicians often neglect to inquire about supplement use. Despite widespread potential interactions, actual clinical harm appears concentrated in high-risk combinations. The review calls for proactive clinical strategies, including standardized supplement screening, targeted patient education, and pharmacist-led medication management. Its limitations include cross-sectional study designs and self-reported data, underscoring the need for longitudinal and intervention-based research. Future studies should prioritize causal evidence, standardized methodologies, and data from low- and middle-income countries to mitigate risks in aging populations.