Automated Dispensing Cabinet Functionality Expansion to Reduce Controlled Substance Inventory Discrepancies

Automated dispensing cabinets have the potential to create technology-induced errors that can arise during controlled substance medication dispensing. Despite enhancements made to the medication use process, the impact of ADC functionality on technology-induced controlled substance discrepancies have yet to be described.

To evaluate the impact of ADC functionality expansion on technology-induced errors such as controlled substance discrepancies created during "blind inventory counts" and cassette dispensing errors.

This quasi-experimental study was conducted over 18 months that evaluated the expanded use of dispensing cassettes within 8 ADCs at the University of Chicago Medicine. Unit-dose controlled substances with high usage were directed for inventory reassignment to cassettes. Controlled substance dispenses, blind inventory counts discrepancies and cassette dispensing errors were evaluated before and after cassette expansion. ADC discrepancy and Cassette Dispensing Error rates were calculated using 1-week segments across the study period.

Of the 64 040 dispenses during the study period, the proportion of cassette dispenses increased from 16% to 72% after cassette expansion. Controlled substance discrepancies decreased from 11 to 7 discrepancies for every 1000 dispenses (P < .0001). After cassette expansion, cassette dispensing errors increased to roughly 28 errors for every 1000 dispenses (P < .0001).

Expansion of ADC functionality created opportunities for reduced technology-induced controlled substance discrepancy rates at the expense of increased cassette dispensing errors.