Introduction: Medication order errors are frequent in Denmark. It is necessary to know the reasons why these errors happen to be able to implement initiatives limiting medication order errors.
Material and methods: In this study we analyzed 811 medications order errors, which were reported as unintended events.
Results: The medication order errors were associated with at total of 98 medicinal product; hence nine medicinal products caused 18 errors with severe or catastrophic harm to patients. 46.0% of the errors were incorrect medicinal product, 47.7% were incorrect dosage and 6.3% of the orders were double ordering. Penicillin and warfarin were the most frequently involved medicinal products. The products that most frequently caused severe or catastrophic patient harm were insulin and warfarin. The most frequent errors were "no medicinal product prescribed" and "incorrect medicinal product". The errors with the most severe consequences for the patients were due to "medication was not discontinued" (sevoflurane and warfarin) and "poor patient compliance" (warfarin and insulin). A common feature concerning the errors' origin was incorrect handling of information.
Conclusion: Specific initiatives should be taken to counter the above-mentioned problems and reduce the occurrence of medication order errors. Such measures may comprise control, medication reconciliation and imposition of clinical decision support.