PURPOSE: Patients with prior allergic reactions to iodinated contrast require premedication. This study aimed to increase the homogeneity of premedication orders in such patients. METHODS: A point-of-care (POC) clinical decision support (CDS) alert accompanied by an order set was implemented in the electronic health record (EHR) to notify providers of a prior allergic reaction upon ordering an examination involving iodinated contrast. Premedication regimens were retrospectively compared 11 months pre- and 11 months post-alert implementation, with the different regimens being classified as follows: (1) "preferred" (per ACR recommendations), (2) "nonpreferred" (corticosteroid administered <24 hours before examination, but not per ACR recommendations), or (3) "no premedication." RESULTS: Over 22 months, 22,023 iodinated contrast examinations were performed, 200 (186 intravascular, 12 gastrointestinal/genitourinary, 1 intraarticular, 1 intrathecal) being in patients with a documented iodinated contrast allergy (106 pre-, 94 post-alert deployment). Prealert, 41 of 106 patients (38.7%) received a preferred regimen, 47 (44.3%) received nonpreferred regimens, and 18 (17.0%) received no premedication. Postalert, 58 of 94 patients (61.7%) received a preferred regimen, 21 (22.3%) nonpreferred regimens, and 15 (16.0%) no premedication. After alert initiation, the patients prescribed a preferred regimen significantly increased (Z-score = 3.25, P = .001), but there was no significant difference in the proportion of patients with no premedication (Z-score = -0.02, P = .85). In 2 of 200 patients (1.0%), an allergic reaction occurred, both after POC-CDS alert implementation with a preferred regimen administered. CONCLUSIONS: The homogeneity of premedication regimens significantly increased after the alert's launch. However, the proportion of patients with no premedication did not significantly change.