Medication errors in home care settings: a 13-year retrospective cohort study in the Ramathibodi Poison Center

INTRODUCTION: Medication errors are a leading cause of preventable harm worldwide, yet evidence has predominantly focused on healthcare settings, with limited data from home care, particularly in Southeast Asia. METHODS: We conducted a retrospective cohort study using 2011-2023 data from the Ramathibodi Poison Center, including patients with medication errors occurring outside healthcare facilities. Clinical effects, management of medication errors, and outcomes were considered as primary outcomes, while the secondary outcome was factors associated with harm, defined as National Coordinating Council for Medication Error Reporting and Prevention Category ≥ E. RESULTS: A total of 925 patients were included. Children (<15 years) accounted for 68.1% of cases, with almost all aged under 10 years. Wrong-drug errors predominated (72.4%), followed by wrong-dose errors (27.4%). Commonly implicated substances included topical dermatologic/antiseptic agents, analgesics, and herbal/traditional products. Medication errors resulting in patient harm were frequent (Category E, 58.6%; Category F, 25.8%), although most cases were managed with supportive care, and no fatalities occurred. In multivariable analysis, underlying disease (adjusted odds ratio 3.10; 95% CI 1.70-5.66) and wrong-drug errors (adjusted odds ratio 2.51; 95% CI 1.67-3.76) were independently associated with harm. DISCUSSION: Home-based medication errors predominantly affected children and were largely driven by caregiver-dependent administration of incorrect medications. The predominance of wrong-drug errors suggests that failures in medication identification and storage, rather than dosing complexity alone, are central mechanisms in this setting. The high proportion of Categories E and F events indicates that these medication errors frequently result in clinically meaningful harm, despite the generally mild clinical presentation. The absence of fatalities might reflect the involvement of commonly available medications and timely access to healthcare services. Factors contributing to harm due to medication errors include the presence of underlying disease and wrong-drug errors. CONCLUSION: Medication errors in home care settings commonly result in temporary harm requiring intervention or hospitalization. Interventions targeting medication identification, caregiver education, and safe storage practices are essential to reduce preventable harm.