(B-144) Trends in Drug-Drug Interactions Among US Older Adults, 2015-2016 vs. 2021-2023

Background: Adverse drug events due to drug-drug interactions are a leading cause of preventable mortality in older adults yet current information on the use of interacting regimens is limited.

Objectives: In this study, we quantify changes in the frequency and types of potential major (contraindicated and generally avoid) drug-drug interactions among older US adults.

Methods: Descriptive analyses of a longitudinal, nationally representative sample of community-dwelling older adults in the U.S. In-home interviews with medication logs were conducted in 2015-2016 and 2021-2023. We used Micromedex to identify potential major drug-drug interactions. Primary outcomes were the prevalence of the concurrent use of medications with a major drug-drug interactions overall and for specific medications.

Results: The study comprised of 4175 participants in 2015-2016 and 2819 in 2021-2023. In 2015-2016, 12.3% of older adults were at risk for a major drug-drug interaction compared with 10.8% in 2021-2023(P =.051). While declines in the use of interacting regimens involving aspirin (3.1% to 1.7%), warfarin (1.3% to 0.4%), and hydrocodone (0.9% to 0.4%) were observed during this time period, increases in the use of citalopram (0.9% to 1.4%), tizanidine (0.2% to 0.6%) and albuterol (0.3% to 0.6%) in interacting combinations was also found (all P< 0.05).

Conclusions: Although the use of interacting medications among older adults has modestly declined since 2015, 1 in 9 is still potentially at risk for a major drug-drug interaction. Improving patient awareness of commonly used drug-drug interactions has the potential to reduce preventable adverse drug events associated with their use among older adults.