[Medication dispensing errors detected in medication cassettes intended for in-hospital patients]

Many dispensing errors occur in hospital pharmacies and can harm patients if they are not intercepted. The aim of this study was to determine the incidence and the primary types of medication dispensing errors at a French military hospital.

The check of unit dose medication cassettes was performed by nurses. From February 2007 to April 2007, detected dispensing errors were systematically recorded and classified into 6 categories: unauthorized drug, wrong dosage-form, improper dose, omission, wrong time, and deteriorated drug errors. The overall error rate was calculated.

During the study, 5112 medication cassettes were checked. 106 dispensing errors have been detected by nurses for a total of 45,573 filled (n=45,518) and omitted (n=55) unit doses. An overall error rate of 0.23% was found. There were approximately 0.02 detected dispensing errors per medication cassette. The most common error types were omission errors (n=55, 51.88%) and improper dose errors (n=30, 28.30%).

The results of this study showed that a check performed by nurses after the dispensing process is necessary to detect the dispensing errors. Many causes may explain the occurrence of dispensing errors and must be corrected. Because some dispensing errors may remain undetected, there is a requirement to develop strategies in order to reduce or eliminate these errors, such as the implementation of a computerized prescribing system. The pharmacy staff is widely involved in this duty.