Iatrogenic Medication Errors Among Older Adults Reported to a Poison Center Network

Iatrogenic medication errors are a preventable source of harm in older adults. Yet their prevalence, types, and outcomes remain poorly characterized. This study aims to describe healthcare-associated iatrogenic medication errors in older adults, including those occurring in the emergency department (ED) and prehospital settings.

An Institutional Review Board-approved retrospective cohort study was conducted among patients aged 65 years and older who had an iatrogenic medication exposure reported to a regional poison center network between January 1, 2020, and May 23, 2025. Cases were extracted from the poison center network's electronic health record and manually reviewed for inclusion as healthcare-associated medication errors. Error severity was assessed using the National Poison Data System (NPDS) medical outcome scale and the National Coordinating Council for Medication Error Reporting and Prevention (NCC MERP) index. Clinical effects, implicated medications, and treatment data were collected and analyzed using descriptive statistics.

Out of 192 potential cases, 182 met inclusion criteria. Most errors occurred in a healthcare setting (nursing facility 32%, non-critical care unit 14%, or ED 12%) and were managed in an ED (60%, 110). Cardiovascular (32%, 129) agents were most often implicated. Most errors occurred during the administration phase (77%, 138), primarily due to medication given to the wrong patient (24%, 43) or at the wrong dose (20%, 36). More than half of cases were classified as NCC MERP Category E or higher, indicating patient harm.

Iatrogenic medication errors in older adults occur across care settings and are most often managed in the ED. While many cause minor harm, a subset results in serious outcomes, with ED-based errors posing higher risk. These findings underscore the need for targeted interventions, particularly during administration and for cardiovascular agents, and provide data to guide strategies and future research to protect this vulnerable population.