PURPOSE: To evaluate numbers and types of drug safety alerts generated and overridden in a large Dutch university medical centre. METHODS: A disguised observation study lasting 25 days on two internal medicine wards evaluating alert generation and handling of alerts. A retrospective analysis was also performed of all drug safety alerts overridden in the hospital using pharmacy log files over 24 months. RESULTS: In the disguised observation study 34% of the orders generated a drug safety alert of which 91% were overridden. The majority of alerts generated (56%) concerned drug-drug interactions (DDIs) and these were overridden more often (98%) than overdoses (89%) or duplicate orders (80%). All drug safety alerts concerning admission medicines were overridden.Retrospective analysis of pharmacy log files for all wards revealed one override per five prescriptions. Of all overrides, DDIs accounted for 59%, overdoses 24% and duplicate orders 17%. DDI alerts of medium-level seriousness were overridden more often (55%) than low-level (22%) or high-level DDIs (19%). In 36% of DDI overrides, it would have been possible to monitor effects by measuring serum levels. The top 20 of overridden DDIs accounted for 76% of all DDI overrides. CONCLUSIONS: Drug safety alerts were generated in one third of orders and were frequently overridden. Duplicate order alerts more often resulted in order cancellation (20%) than did alerts for overdose (11%) or DDIs (2%). DDIs were most frequently overridden. Only a small number of DDIs caused these overrides. Studies on improvement of alert handling should focus on these frequently-overridden DDIs.

Additional Metadata
Keywords *Academic Medical Centers/statistics & numerical data, *Decision Support Systems, Clinical, *Drug Therapy, Computer-Assisted/statistics & numerical data, *Medical Order Entry Systems/statistics & numerical data, *Pharmacy Service, Hospital/statistics & numerical data, *Reminder Systems/statistics & numerical data, Drug Interactions, Drug Prescriptions, Hospital Units, Humans, Internal Medicine, Medication Errors/*prevention & control/statistics & numerical data, Netherlands, Overdose/prevention & control, Retrospective Studies, Time Factors, alert, computer assisted, computerized physician order entry, drug therapy, error, override, patient safety
Persistent URL dx.doi.org/10.1002/pds.1800, hdl.handle.net/1765/19379
Citation
van der Sijs, I.H., Mulder, A., van Gelder, T., Aarts, J.E.C.M., Berg, M., & Vulto, A.G.. (2009). Drug safety alert generation and overriding in a large Dutch university medical centre. Pharmacoepidemiology and Drug Safety: an international journal, 18(10), 941–947. doi:10.1002/pds.1800