Nature and causes of clinically significant medication errors in a tertiary care hospital.

PURPOSE: Medication errors identified through solicited error reports in general medicine and specialty units of a major tertiary care teaching hospital were studied to identify prevalent patterns and causes. METHODS: Medication error reports by a multidisciplinary team of eight clinicians at adult medical and surgical, hematology and oncology, bone marrow transplantation, and medical and cardiac intensive care units were collected prospectively over a three-month period. The reports were validated in terms of clinical significance, causality, and true presence of an error by two independent reviewers. Cluster analysis of valid reports (reports accepted by both reviewers) was used to identify prominent error patterns. RESULTS: Of 321 medication error reports, 240 were included in the analysis. Of these, 95 represented manifested errors and the rest near misses (not manifested [94] or averted [51]). Most manifested errors involved uncontrolled infections associated with prescribed underdoses of antiinfectives (23%), renal failure associated with prescribed overdoses of antiinfectives (4%), central-nervous-system drug intoxication following prescribed overdoses (4%), or uncontrolled pain associated with prescribed underdoses (4%). Most errors were initiated during prescribing (72%) and were associated with deficits in pharmacotherapy knowledge (39%) or with failure to consider critical patient information (18%). Errors initiated during dispensing and administration were mostly associated with performance deficits (e.g., accidental slips and lapses). CONCLUSION: A limited number of prevalent medication-error patterns described more than half of all reported errors in a hospital and suggested excellent areas for quality improvement. Error causes varied with the node of the medication-use process where they arose and suggested the need for tailored interventions to improve clinicians' performance.