CancelRx System Reduced Drug Dispensing on Discontinued Scripts

Implementation of an e-prescription cancellation messaging system was associated with a reduction in the proportion of medications sold after the prescriptions had been discontinued in the electronic health record (EHR), according to a case series with interrupted time series analysis.

The proportion of medications dispensed within 6 months of the prescription's discontinuation in the EHR dropped from a baseline of 8% to 1.4% (P<0.001) in the year after implementation of the CancelRx system, without a significant week-to-week trend (β=0.000158; P=0.37) reported Samantha I. Pitts, MD, MPH, of the Johns Hopkins University School of Medicine in Baltimore, and colleagues.

"Implementation of CancelRx also reduced variation by pharmacy and by medication class in the proportion of medications dispensed after discontinuation in the EHR, with the greatest reductions among immunosuppressants, anticoagulants and antiplatelet drugs, and cardiovascular medications," the authors wrote in JAMA Internal Medicine.

"This significant reduction in dispensing of prescriptions after discontinuation in the EHR suggests that CancelRx implementation may reduce medication dispensing errors by communicating intended medication changes to pharmacies," they added.

An estimated one in 30 people are harmed by medication errors, with one in four of those cases resulting in severe or life-threatening harm, Pitts and team noted. Among the estimated 1.5% to 5% of medications that continue to be dispensed even after the prescriber has discontinued them, 34% are at high risk of causing harm.

These risks led the National Council for Prescription Drug Programs to develop CancelRx, which allows EHRs to send electronic cancellation messages for Surescripts e-prescriptions to a pharmacy, much like the e-prescribing process, the authors explained.

Previous findings have already shown that CancelRx successfully cancels more than 90% of e-prescription transactions and reduces inconsistencies between the EHR and pharmacy management systems, but research has also found that CancelRx is under-utilized. An estimated 57% of prescribers and 84% of pharmacies had enabled CancelRx in 2020, according to the Surescripts National Progress Report that year. Greater uptake "could significantly improve medication safety," Pitts and co-authors concluded.

Grace Zhang, MD, and Deborah Grady, MD, MPH, both of the University of California San Francisco, also pointed out the need to increase use of the CancelRx system to reap its patient safety benefits in an Editor's Note.

"This reduction highlights the importance of implementing CancelRx in e-prescription systems, which unfortunately only few health systems have done," they wrote.

Even with more widespread utilization, however, room for improvement remains, they suggested.

"Even with the adoption of CancelRx, it is clear that we have not yet achieved a perfect system," they wrote. "There continue to be limitations, including missed or unsent CancelRx messages or pharmacies not participating in CancelRx."

Still, the substantial reduction in filling discontinued medications shows the value of CancelRx, they added.

Among other current limitations of CancelRx noted by the study authors are the inability of pharmacy staff to see the prescriber's reasons for discontinuing a prescription, the inability of prescribers to see transaction outcomes in their current workflows (to confirm the prescription was actually discontinued at the pharmacy), the need to prioritize the highest-value messages to reduce noise in the system, and the inability of CancelRx to cancel prescriptions written from outside the local EHR.

"With states such as California implementing new e-prescription mandates and the continued rise of e-prescriptions, we need to address the issue of electronic deprescribing as quickly as possible and mitigate harm to patients," Zhang and Grady wrote.

In the study, an urban academic medical center implemented CancelRx in January 2019 for all prescriptions sent from the ambulatory practices' single EHR system to the health system's 11 pharmacies. The 2-year study period ran from 1 year before the CancelRx implementation until 1 year after.

Pitts and colleagues analyzed data on 53,298 e-prescriptions sent by 3,986 prescribers for all 17,451 patients who had at least one e-prescribed medication discontinued during the study period, excluding over-the-counter medications and topic, otic, and ophthalmic drugs.

After implementation of CancelRx, 85.9% of 26,127 discontinued e-prescriptions triggered a CancelRx message. Among the discontinued prescriptions that CancelRx didn't send, 6.3% were discontinued as a duplicate, and 7.8% had no known reason for CancelRx not sending them.

The median time between sending the e-prescription and discontinuation was similar before (56 days) and after (54 days) implementing CancelRx. The proportion of medications reordered within 120 days after discontinuation was also similar before (10.4%) and after (10.8%; P=0.15) CancelRx implementation -- a secondary outcome assessed to ensure CancelRx did not lead to unintended discontinuations.

Before CancelRx's implementation, both pharmacies and drug classes varied substantially in rates of discontinued prescriptions that were sold to patients, but these evened out after CancelRx. The mean proportion of medications dispensed after discontinuations across drug classes ranged from 3.9% to 12.5% before CancelRx implementation to 0.7% to 3.7% afterward. Across pharmacies, the mean proportion of medications dispensed after discontinuation ranged from 4.5% to 12.4% before CancelRx to 0.4% to 2.2% after.

Pitts and team noted that the analysis was limited to dispensing up to 6 months after discontinuation, although a prescription could have been dispensed for up to 12 months.

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