31 Background: In 2013 Cancer Care Ontario released updated antiemetic recommendations supporting the use of aprepitant-based combinations as 1st line therapy for highly emetogenic and 2nd line therapy for moderately emetogenic chemotherapy and discouraging the prolonged use of 5-HT3 antagonists. In 2014 changes were made in the Ontario drug formulary to align public funding to those recommendations. The impact of the changes in guidance and public funding on prescribing practices are now being analyzed. Methods: Using the Ontario Drug Benefit (ODB) database, data was extracted to analyze the prescribing practices of aprepitant, granisetron and ondansetron for chemotherapy-induced emesis between the pre-funding period (November 2013 to September 2014) and post-funding period (October 2014 to July 2015). Results: Prior to funding changes, an average of 197 prescriptions/month of aprepitant were billed to the ODB program totaling $22,422. After funding, an average of 1,165 prescriptions/month of aprepitant were billed totaling $132,145. This represented a 490% increase in utilization. The combined 5-HT3 receptor antagonists prescriptions/month billed during the respective time periods were 5,592 ($405,604) and 5,536 ($402,628). This represented a 1% decrease in utilization. Conclusions: There was a significant increase in aprepitant utilization and total expenditure to the ODB program indicating strong uptake of the triple-drug recommendation for highly emetogenic regimens. However, there was minimal change in prescribing practices related to the 5-HT3 receptor antagonists, indicating a reluctance to decrease utilization. Further work is necessary to discourage the prolonged use of 5-HT3 receptor antagonists.