297 Background: Azole-antifungals like posaconazole and voriconazole have a documented significant risk of adverse drug events (ADE) when concomitantly administered with vinca-alkaloid chemotherapy (vincristine, vinblastine, vinorelbine) due to inhibition of vinca clearance. Potential ADE’s include paralytic ileus, severe, potentially permanent neuropathies, cranial nerve dysfunction, seizures, etc. Aim: Assess a standardized process to hold azole-antifungal around vinca-alkaloid drug administration to decrease the risk of adverse events associated with this drug-drug interaction in pediatric oncology patients. Intervention: Azole-antifungals (fluconazole*, voriconazole, posaconazole, itraconazole) will be held the day before, day of, and day after the vinca-alkaloid administration (with flexibility given provider discretion*) in the outpatient and inpatient setting at a single site. Methods: Development of a Standard Operating Procedure (SOP), informational technology (IT) processes such as Best Practice Advisory (BPA), nursing orders, Vinca Time-Out order and standard nursing note template for telephone encounter to remind patient/parents. Retrospective data was assessed in three 6-12 month phases, Pre-SOP (Phase 0), Post- SOP and Pre-IT support (Phase 1), and Full implementation (Phase 2). Study Outcomes: 1.Hold the azole-antifungal in 100% of encounters where vinca-alkaloid is due. 2. Decrease number of adverse events by 10%. 3. Maintain adequate fungal prophylaxis (or treatment) with a 0% incidence of breakthrough fungal infections. Results: Average number of concomitant azole/vinca administrations for each Phase was 39. A 97% improvement was seen in the number of vinca administrations dose reduced or held from 28 (Phase 0) to 1 (Phase 2). A 66% improvement in SOP compliance was observed (19 % in Phase 0, and 85% in Phase 2). Significant adverse effects were decreased by 33-50% between Phase 0, and Phase 1 and 2, respectively. Three patients in Phase 2 experienced fungal infection breakthrough; all had documented compliance issues prior to the study period. Conclusions: Implementation of the SOP and IT processes helped achieve a process to hold azole antifungals and led to significant decrease in the need to dose reduce or hold vinca-alkaloids thereby allowing less chemotherapy interruption/dose adjustments. Further modification of the SOP may be developed to exclude those patients on anti-fungal therapy for an active fungal infection.