Fosaprepitant and Aprepitant for Chemotherapy-Induced Nausea and Vomiting in Children

Marcia L. Buck, PharmD, FCCP, FPPAG, BCPPS


Pediatr Pharm. 2018;24(6) 

In This Article

Mechanism of Action

Fosaprepitant dimeglumine is a prodrug of aprepitant, a high-affinity substance P/neurolinin-1 (NK1) receptor antagonist.[1] Aprepitant has little or no affinity for dopamine, serotonin (5-HT3), or corticosteroid receptors, giving it a unique mechanism of action compared to other currently available antiemetics. Occupancy of NK1 receptors in the corpus striatum is associated with an antiemetic effect that augments the effects of 5-HT3 antagonists and corticosteroids. Studies conducted using positron emission tomography have shown that at plasma concentrations of 10 ng/mL, aprepitant occupies approximately 50% of brain NK1 receptors and at 100 ng/mL, occupies approximately 90%. The exact percentage of NK1 receptor blockade and its relationship to antiemetic efficacy has not been established.