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Analysis of iatrogenic and in-hospital medication errors reported to United States poison centers: a retrospective observational study


Background and objective

Medication errors are common in healthcare settings. Previous poison-center studies have evaluated medication errors, but not specifically iatrogenic or in-hospital errors. The purpose of this study was to describe errors attributed to healthcare professionals or occurring in a healthcare facility reported to poison centers.


This was a retrospective study of medication errors reported to the US National Poison Data System from 2000 through 2017. Inclusion criteria were reason for exposure coded “unintentional, therapeutic error”, error scenario of health professional/iatrogenic error, or the location of exposure was in a healthcare facility. Variables assessed for each case included age, medication class, error scenario, medical outcome, and day of week and time case initiated. Descriptive statistics were performed.


There were 99,431 cases included. Median age was 20 years (interquartile range: 3–53), with ages ranging from 1 day to 108 years; 50.0% of cases were female. The most frequently reported medication categories were antimicrobials (13.6%), followed by analgesics (10.1%), then sedatives/hypnotics (8.9%), although the classes of drugs varied by age group. The most common error scenarios were “wrong medication taken or given,” “other incorrect dose,” and “incorrect dosing route,” although these differed by age group with more “other incorrect dose” reported in 0–5 years and “wrong medication taken or given” predominating in the other age groups. Serious effects (death and major effect) occurred at a higher frequency in the 65 + years age group than in all other age groups. The time of day with the most cases was 7–9 pm, with the lowest around 3–5 am. Fewer cases were reported on weekends than during the other days of the week.


This study provides a more detailed evaluation of iatrogenic and in-hospital errors reported to poison centers and their related scenarios. Prevention efforts should continue to focus on reducing the incidence of errors with an emphasis on reducing the most frequent errors.

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This study was presented in poster format at the 2018 American Society of Health-System Pharmacists Midyear Clinical Meeting. The American Association of Poison Control Centers (AAPCC) maintains the National Poison Data System (NPDS), which houses de-identified case records of self-reported information collected from callers during exposure management and poison information calls managed by the country’s poison control centers (PCCs). NPDS data do not reflect the entire universe of exposure to a particular substance as additional exposure may go unreported to PCCs; accordingly, NPDS data should not be construed to represent the complete incidence of US exposures to any substance(s). Exposures do not necessarily represent a poisoning or overdose and the AAPCC is not able to completely verify the accuracy of every report. Findings based on NPDS data do not necessarily reflect the opinions of the AAPCC.

Author information




JBL designed the study, acquired and interpreted the data, and wrote the first draft. CM interpreted the data and wrote the first draft. AAF assisted in study design and critically revised the manuscript. WK-S assisted in study design and critically revised the manuscript. All authors read and approved the final manuscript.

Corresponding author

Correspondence to James B. Leonard.

Ethics declarations


No funding was secured for this study. The authors have no financial relationships relevant to this article to disclose.

Ethical approval

This study was determined to be “Not-Human Subject Research” by the Institutional Review Board.

Conflict of interest

James B. Leonard, Chelsea McFadden, Agnes Ann Feemster, and Wendy Klein-Schwartz have no conflicts of interest relevant to this article to disclose.

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Leonard, J.B., McFadden, C., Feemster, A.A. et al. Analysis of iatrogenic and in-hospital medication errors reported to United States poison centers: a retrospective observational study. Drugs Ther Perspect 36, 190–201 (2020).

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