Errors in the medication process: frequency, type, and potential clinical consequences

Int J Qual Health Care. 2005 Feb;17(1):15-22. doi: 10.1093/intqhc/mzi015.


Objective: To investigate the frequency, type, and consequences of medication errors in more stages of the medication process, including discharge summaries.

Design: A cross-sectional study using three methods to detect errors in the medication process: direct observations, unannounced control visits, and chart reviews. With the exception of errors in discharge summaries all potential medication error consequences were evaluated by physicians and pharmacists.

Setting: A randomly selected medical and surgical department at Aarhus University Hospital, Denmark.

Study participants: Eligible in-hospital patients aged 18 or over (n = 64), physicians prescribing drugs and nurses dispensing and administering drugs.

Main outcome measures: Frequency, type, and potential clinical consequences of all detected errors compared with the total number of opportunities for error.

Results: We detected a total of 1065 errors in 2467 opportunities for errors (43%). In worst case scenario 20-30% of all evaluated medication errors were assessed as potential adverse drug events. In each stage the frequency of medication errors were-ordering: 167/433 (39%), transcription: 310/558 (56%), dispensing: 22/538 (4%), administration: 166/412 (41%), and finally discharge summaries: 401/526 (76%). The most common types of error throughout the medication process were: lack of drug form, unordered drug, omission of drug/dose, and lack of identity control.

Conclusion: There is a need for quality improvement, as almost 50% of all errors in doses and prescriptions in the medication process were caused by missing actions. We assume that the number of errors could be reduced by simple changes of existing procedures or by implementing automated technologies in the medication process.

MeSH terms

  • Adult
  • Cross-Sectional Studies
  • Delivery of Health Care
  • Humans
  • Medical Audit
  • Medication Errors*
  • Quality Control
  • Quality of Health Care*
  • Safety Management*
  • Systems Analysis