National observational study of prescription dispensing accuracy and safety in 50 pharmacies.

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.