We do not currently know of any antonyms for aprepitant.
The noun aprepitant is defined as:
An antagonistdrug, 5-[[(2S,3R)-2-[(1R)-1-[3,5-bis(trifluoromethyl)phenyl] ethoxy]-3-(4-fluorophenyl)morpholin-4-yl] methyl]-1,2-dihydro-1,2,4-triazol-3-one, used to prevent nausea following chemotherapy