Compatibility of intravenous fosaprepitant with intravenous 5-HT3 antagonists and corticosteroids.

Fosaprepitant dimeglumine for injection is the water-soluble phosphorylated prodrug of the neurokinin-1 receptor antagonist aprepitant. Both agents are approved (in combination with a 5-HT3 antagonist and a corticosteroid) for prevention of chemotherapy-induced nausea and vomiting. Because fosaprepitant is likely to be combined and stored in the same intravenous (IV) bag with 5-HT3 antagonists and corticosteroids, the in vitro compatibility of fosaprepitant with these agents and other IV diluents was assessed. Fosaprepitant (1 mg/mL in 0.9 % sodium chloride injection solution) was combined in binary or tertiary fashion with therapeutic-dose preparations of a 5-HT3 antagonist (ondansetron, granisetron, palonosetron, or tropisetron) and/or a corticosteroid (dexamethasone sodium phosphate or methylprednisolone sodium succinate). For diluent compatibility assessment, fosaprepitant was also prepared 1 mg/mL in 0.9 % sodium chloride injection solution, water for injection, or 5 % dextrose injection solution. After 24-h storage under ambient conditions, samples were assayed for degradation. Fosaprepitant demonstrated compatibility when combined in the same IV infusion bag with common 5-HT3 antagonists and corticosteroids for storage and IV coadministration, with the exception of palonosetron (incompatible under all experimental conditions) and tropisetron (incompatible unless combined with a corticosteroid). No incompatibility was observed between fosaprepitant and any of the 3 diluents tested. Use of fosaprepitant in combination with other antiemetics may provide a flexible option for administration of antiemetics to patients receiving moderately or highly emetogenic chemotherapy.