Neurokinin 1 (NK1) receptor antagonists are in a class of drug used to treat nausea and vomiting associated with chemotherapy. Aprepitant, casopitant, fosaprepitant, and rolapitant are NK1 drugs. In January 2018, the FDA posted a warning​ about ​Varubi® (rolapitant) injectable emulsion, which is used for prevention of delayed CINV in adults, ​and the risk of anaphylaxis, anaphylactic shock and other serious hypersensitivity reactions. ​There is some evidence that fosaprepitant may be more helpful in the prevention of delayed nausea and vomiting (dos Santos, Souza, Brunetto, Sasse, & Lima, 2012). NK1 antagonists are effective for both adult and pediatric patients. However, the use and most appropriate dosing among pediatric patients of various age groups has not been determined.

dos Santos, L.V., Souza, F.H., Brunetto, A.T., Sasse, A.D., & Lima, J.P.D.S.N. (2012). Neurokinin-1 receptor antagonists for chemotherapy-induced nausea and vomiting: A systematic review. Journal of the National Cancer Institute, 104, 1280–1292. doi:10.1093/jnci/djs335