Objectives: To measure dispensing accuracy rates in 50 pharmacies located in 6 cities across the United States and describe the nature and frequency of the errors detected.
Design: Cross-sectional descriptive study.
Settings: Chain, independent, and health-system pharmacies (located in hospitals or managed care organizations).
Participants: Pharmacy staff at randomly selected pharmacies in each city who accepted an invitation to participate.
Intervention: Observation by a pharmacist in each pharmacy for 1 day, with a goal of inspecting 100 prescriptions for dispensing errors (defined as any deviation from the prescriber's order).
Main outcome measure: Dispensing errors on new and refill prescriptions.
Results: Data were collected between July 2000 and April 2001. The overall dispensing accuracy rate was 98.3% (77 errors among 4,481 prescriptions; range, 87.2%-100.0%; 95.0% confidence interval, +/- 0.4%). Accuracy rates did not differ significantly by pharmacy type or city. Of the 77 identified errors, 5 (6.5%) were judged to be clinically important.
Conclusion: Dispensing errors are a problem on a national level, at a rate of about 4 errors per day in a pharmacy filling 250 prescriptions daily. An estimated 51.5 million errors occur during the filling of 3 billion prescriptions each year.