Pharmacy prescription dispensing errors reported to a regional poison control center

Objectives: To identify the incidence, types, associations, and outcomes of pharmacy prescription dispensing errors reported to a regional poison control center. Methods: Retrospective chart review over a 35-month period. Results: Of 77,992 drug exposures reported, there were 6450 unintentional therapeutic exposures. Forty were the result of pharmacy prescription dispensing errors. Of these, 20 (50%) were medication substitution errors (wrong drug), 17 (42.5%) were labeling errors (correct drug, wrong formulation or instructions), and 3 (7.5%) were compounding errors (incorrect liquid dilution or capsule preparation). Both compounding and labeling errors were significantly more likely than substitution errors to be order-of-magnitude amounts. Compounding errors were also significantly more likely than labeling errors to be order-of-magnitude amounts. Labeling errors were significantly more likely to be liquids prescribed to children than substitution errors. Compounding errors had significantly more serious outcomes compared with substitution or labeling errors. Conclusions: Substitution and labeling errors are the most common pharmacy prescription dispensing errors reported to a regional poison control center. Compounding errors have the greatest potential for serious outcomes. Children are particularly at risk because of the increased potential for error in the preparation and use of liquids. Inclusion of scenarios of prescription dispensing errors in the Toxic Exposure Surveillance System database would improve error detection and tracking. Poison control centers may be a source of valuable feedback to physicians and pharmacists.