Prospective study of the incidence, nature and causes of dispensing errors in community pharmacies.

Background: Each year over 600 million prescription items are dispensed in community pharmacies in England and Wales. Despite this, there is little published evidence relating to dispensing errors and near misses occurring in this setting. This study sought to determine their incidence, nature and causes.

Methods: Prospective study over a 4-week period in 35 community pharmacies (9 independent pharmacies and 26 chain pharmacies) in the UK. Pharmacists recorded details of all incidents that occurred during the dispensing process, including information about: the stage at which the error was detected; who found the error; who made the error; type of error; reported cause of error and circumstances associated with the error.

Results: 125,395 prescribed items were dispensed during the study period and 330 incidents were recorded relating to 310 prescriptions. 280 (84.8%) incidents were classified as a near miss (rate per 10,000 items dispensed=22.33, 95%CI 19.79-25.10), while the remaining 50 (15.2%) were classified as dispensing errors (rate per 10,000 items dispensed=3.99, 95%CI 2.96-5.26). Selection errors were the most common types of incidents (199, 60.3%), followed by labeling (109, 33.0%) and bagging errors (22, 6.6%). Most of the incidents were caused either by misreading the prescription (90, 24.5%), similar drug names (62, 16.8%), selecting the previous drug or dose from the patient's medication record on the pharmacy computer (42, 11.4%) or similar packaging (28, 7.6%).

Conclusions: This study has demonstrated that a wide range of medication errors occur in community pharmacies. On average, for every 10,000 items dispensed, there are around 22 near misses and four dispensing errors. Given the current plans for reporting adverse events in the NHS, greater insight into the likely incidence and nature of dispensing errors will be helpful in designing effective risk management strategies in primary care.