title: Medication errors detected in non-traditional databases: types of errors in methotrexate dosing as listed in four different Danish registers.
abstract: OBJECTIVE
  We have looked for medication errors involving the use of low-dose methotrexate, by extracting information from Danish sources other than traditional pharmacovigilance databases. We used the data to establish the relative frequencies of different types of errors.
  
  
  METHODS
  We searched four databases for cases involving low-dose methotrexate between 1999 and 2011: the Danish Patient Safety Databases (DPSD), controlled by the Danish National Agency for Patients' Rights and Complaints, the Patient Compensation Association (PCA), the Danish Poison and Information Centre (DPIC), and the online database of the Department for Patient Complaints (DPC). We categorized the place where the error occurred, the processes and types of error involved, the person responsible, and the clinical outcome.
  
  
  RESULTS
  We identified 173 errors. In 109 (63%), either harm resulted or could not be excluded; of these, 26 (15%) resulted in serious harm, including nine deaths (5%); 53 (31%) involved incorrect daily administration; and 107 (62%) involved a dosing error. Sixteen events (9.2%) concerned insufficient or faulty monitoring, with four serious outcomes and two deaths. Prescription errors involving daily rather than weekly administration, by hospital physicians, were most likely to result in serious outcomes, including deaths. The error mechanism was evaluated in 129 events. Action-based errors comprised 50 % and knowledge-based errors 34 %. Action-based errors were more likely to result in completed errors, whereas knowledge-based errors more often resulted in near misses.
  
  
  CONCLUSIONS
  The medication errors in this survey were most often action-based (50%) and knowledge-based (34%), suggesting that greater attention should be paid to education and surveillance of medical personnel who prescribe and monitor methotrexate, particularly physicians, who accounted for 40% of the errors.
authors.affiliation: Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark. hperregaard@yahoo.com.
authors.forename: Helene
authors.initials: H
authors.lastname: Perregaard
authors.affiliation: Nuffield Department of Primary Care Health Sciences, University of Oxford, New Radcliffe House, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, UK.
authors.forename: Jeffrey K
authors.initials: JK
authors.lastname: Aronson
authors.affiliation: Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.|Department of Clinical Pharmacology and the Danish Poison Information Center, Bispebjerg Hospital, Capital Region of Denmark, Copenhagen, Denmark.
authors.forename: Kim
authors.initials: K
authors.lastname: Dalhoff
authors.affiliation: Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.|Unit for Quality and Patient Safety, Capital Region of Denmark, Copenhagen, Denmark.
authors.forename: Annemarie
authors.initials: A
authors.lastname: Hellebek
mesh_terms: D018501:Antirheumatic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D016208:Databases, Factual / Q000706:statistics & numerical data; D003718:Denmark; D003879:Dermatologic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D006801:Humans; D008508:Medication Errors / Q000706:statistics & numerical data*; D008727:Methotrexate / Q000009:adverse effects* / Q000627:therapeutic use
chemical_list: D018501:Antirheumatic Agents; D003879:Dermatologic Agents; D008727:Methotrexate
keywords: Medication errors; Methotrexate; Pharmacovigilance databases