Discontinuation of outpatient medications: implications for electronic messaging to pharmacies using CancelRx.

Electronic communication of prescription discontinuation, or CancelRx, has the potential to improve medication safety. We aimed to describe the proportion of discontinued outpatient medications that would result in a CancelRx message to understand its impact on medication safety. We used a data report to identify all outpatient medications discontinued in the electronic health record (EHR) of an academic health system in 1 month (October 2018). Among all 63 485 medications discontinued, 23 118 (36.4%) were e-prescribed, 25 982 (40.9%) were patient-reported or reconciled, and the remainder prescribed nonelectronically. Discontinued high-risk medications were more likely to be e-prescribed (2768 of 5896, 47.0%). A discontinuation reason was specified in 37 353 (58.9%) of all discontinued medications. Approximately one-third to one-half of discontinued medications were e-prescribed within the same EHR and would result in a CancelRx message to the pharmacy. Extension of this functionality to medications reconciled in the EHR could significantly expand the impact of CancelRx on medication safety. In addition, complete and accurate discontinuation reasons are needed to optimize CancelRx implementation.