Pharmacists' Workload Contributes To Errors

The study was conducted by a team of researchers led by College of Pharmacy professor Daniel C. Malone, Ph.D., who is also a member of the Arizona Center for Education and Research on Therapeutics at the Critical Path Institute.

Researchers reviewed data submitted to insurance companies from 672 pharmacies in 18 metropolitan regions. The pharmacies filled an average of 18,000 prescriptions from January to March 2003, or 1,375 prescriptions per week. During that time, the average number of potentially harmful drug-drug interactions dispensed by each pharmacy was 32.1.

The pharmacies employed an average of 1.2 pharmacists for each hour the store was open, and each pharmacist filled an average of 14.1 prescriptions per hour. The risk of dispensing potentially harmful combinations of medications that could result in a drug interaction increased by 3 percent for each additional prescription filled per hour.

The study also found that computerized interaction alerts and telephone, Internet, and fax systems—which are intended to decrease pharmacist workload and increase the efficiency of prescription receipt and filling—also were associated with an increase in the number of prescriptions dispensed for medications that could interact.

“It appears that prescription volume is exceeding capacity and that automation and other pharmacy staffing may not sufficiently compensate for the increased pharmacist workload,” Malone says. “Additional research is needed to confirm and clarify this study, but our findings are consistent with other reports concerning workload and medication errors. We need to take a closer look at what we can do better in community pharmacies to reduce potentially dangerous interactions between dispensed medicines.”

The study was supported by a grant from the Agency for Healthcare Research and Quality’s Centers for Research and Education on Therapeutics (CERTs) program.