Characterization of errors detected during central order review.

Characterization of prescribing errors detected by dispensary pharmacists in a tertiary-care teaching hospital is described. During the 25 week study period, 1330 prescribing errors were identified from a total of 237,798 medication orders processed by the pharmacy, representing a rate of 5.6 errors per 1000 orders. Resident physicians wrote more errant medication orders than any other physician class. Errors most often occurred on the general medicine teaching wards. The most common drug classes implicated were non-formulary medications and antibiotics. Approximately 11% of errors were defined as potentially fatal or severe (Type A) errors, 7% were potentially serious (Type B), 21% were potentially significant (Type C) and 61% were problem orders (Type D) based on a classification system of severity. The most common error types were inappropriate dosing of antibiotics and the prescribing of medications for patients who had a potential conflicting allergy history. The acceptance of pharmacists' suggestions was 67%. The study identified three major areas where future educational and corrective measures could be aimed: adherence to the formulary, antibiotic prescribing and allergy validation.