3. Duplicative Therapy

Aprepitant is the first medication in the class of selective human substance P/NK1 antagonists. Cinvanti® (aprepitant) intravenous emulsion is indicated for use on day 1 of the chemotherapy cycle, and oral aprepitant is indicated on days two and three for moderate emetic risk chemotherapy regimens¹⁰. Fosaprepitant, the injectable aprepitant formulation, was indicated for use on day 1 of the chemotherapy cycle as the 115 mg dose with oral aprepitant administered on days 2 and 3; however, the 115 mg vial is no longer commercially available. Fosaprepitant 150 mg injection is not administered with oral aprepitant on any treatment days⁵. Dosage regimens incorporating concurrent use of fosaprepitant 150 mg and aprepitant will be reviewed. Concurrent administration of selective human substance P/NK1 receptor antagonists is not supported in the literature and may result in enhance adverse pharmacologic effects. Additionally, combined use of oral rolapitant or netupitant/palonosetron is not indicated and may result in increased adverse effects. Combined use of substance P/NK1 receptor antagonists or adjunctive use of oral and parenteral substance P/NK1 receptor antagonist formulations is not recommended and will be reviewed.