Incidence, type and causes of dispensing errors: a study from the community pharmacy

Objectives: To evaluate the incidence, type and potential causes of dispensing errors. Methods: A Prospective study was conducted at a community pharmacy in Madrid (Spain). Every prescription filled while the investigator was present was inspected. A sample of will-call prescriptions (filled before the arrival of the investigator and waiting to be picked up) were inspected. Investigators compared the physician’s written order to the contents and label of each new prescription (patient presented a new prescription to the pharmacy staff). Any deviations from the prescribed order were noted as errors. Errors observed during the study were categorized according to into two major groups: content and labeling errors. Absolute and relative frequencies as percentages for qualitative variables and the mean, for quantitative variable age were calculated. To compare whether the number of errors is distributed evenly across the dichotomous variable "team member who makes the mistake" was used chi-square test by setting p = 0.05. Results: In all, 12 000 prescriptions were dispensed and 55 incidents were recorded during the 3-months study period. The rate of incidents per 1000 items dispensed was 4.58 (95%CI 4.22–0.25). Seventeen incidents (31.5%) were classified as a dispensing the wrong drug strength error (rate per 1000 items dispensed 4.22), followed by others dispensing errors (25.9%). The main reported causes of the incidents involved misreading the prescription (15, 27.3%), similar drug names (10, 18.2%) and similar packaging (9, 16.4%). Dispensing errors were significantly more likely to be made by the pharmacy technician. Conclusion: The total dispensing error rate in the study sample was independent of other comparative studies. The categories "labeling error" represented a small influence on the total error rate. Misread prescription, similar drug name and similar packaging were the most prevalent causes of dispensing.