Classification and Definitions of Error Types
Types of medication errors and their definitions have been described in various sources.2,16- 20 These have been adapted and incorporated in the list below to classify the types of medication errors that occurred within our institution.
Missing or Inaccurate Allergy Information:
Order received in pharmacy without proper allergy information or allergy information conflicting with existing pharmacy database. Prescribers are responsible for the communication of allergy information to the pharmacy.
Patient had a known allergy to, or a possible cross-sensitivity to, prescribed medication; pharmacist intervention required to alter therapy.
Improper Dose/Quantity or Omitted Dose/Quantity:
Improper dose strength was prescribed or dose strength was omitted from the medication order.
This would include failure to specify medication formulation when more than 1 formulation was available.
Improper or Omitted Route of Administration:
Improper route of administration was prescribed or route was omitted from medication order.
Improper or Omitted Frequency:
Incorrect medication frequency was prescribed or omitted from the order.
Medication Omission Error:
Prescriber inadvertently omitted a medication or treatment from admission, transfer, or postoperative orders. Also includes a patient having an indication for which no treatment or inadequate treatment was prescribed.
Two or more medications in the same therapeutic class were prescribed for the patient resulting in unnecessary therapeutic duplication.
A medication was prescribed that had a potential interaction with current drug regimen; pharmacist intervention was required to alter therapy.
A medication was prescribed that had a potential interaction with current dietary orders; pharmacist intervention was required to alter therapy.
Incorrect Medication or Unspecified Medication:
Medication ordered was not appropriate for patient based on indication, patient-specific variables, or clinical status. Orders for "patient may take own medication(s)" without specifying the exact medication and directions would also fall into this category.
This category would include restricted medications ordered by a prescriber who was not authorized to do so at our institution (eg, an antibiotic restricted for use by the infectious diseases service only). A medication was ordered that was not on the formulary at our institution.
Incorrect Treatment Duration:
Medication was prescribed without an appropriate stop time when such is indicated (eg, injectable ketorolac without the 5-day limit specified).
Order received in the pharmacy that could not be processed owing to illegible handwriting, inappropriate abbreviation(s), and/or difficulty in interpreting what was meant by the order. This required further clarification with the prescriber and/or chart review.
Missing or Inaccurate Height/Weight:
Patient's height and/or weight were missing or inaccurate where needed for height- and/or weight-based medication doses (eg, chemotherapy).
Improper/Omitted Medication Rate:
The medication rate (when required) was omitted or incorrect for the specific medication, patient-specific variables, and/or clinical status.