Title: Aprepitant
CAS Registry Number: 170729-80-3
CAS Name: 5-[[(2R,3S)-2-[(1R)-1-[3,5-Bis(trifluoromethyl)phenyl]ethoxy]-3-(4-fluorophenyl)-4-morpholinyl]methyl]-1,2-dihydro-3H-1,2,4-triazol-3-one
Additional Names: (2R)-[(1R)-3,5-bis(trifluoromethyl)phenylethoxy]-(3S)-(4-fluoro)phenyl-4-(3-oxo-1,2,4-triazol-5-yl)methyl morpholine
Manufacturers' Codes: MK-0869
Trademarks: Emend (Merck & Co.)
Molecular Formula: C23H21F7N4O3
Molecular Weight: 534.43
Percent Composition: C 51.69%, H 3.96%, F 24.88%, N 10.48%, O 8.98%
Literature References: Selective neurokinin-1 (NK-1) receptor antagonist. Prepn: C. P. Dorn et al., WO 9516679; eidem, US 5719147 (1995, 1998 both to Merck & Co.); and pharmacology: J. J. Hale et al., J. Med. Chem. 41, 4607 (1998). Improved synthesis: K. M. J. Brands et al., J. Am. Chem. Soc. 125, 2129 (2003). LC/MS/MS determn in plasma: C. M. Chavez-Eng et al., J. Pharm. Biomed. Anal. 35, 1213 (2004). Clinical trial in prevention of cisplatin-induced emesis: S. Van Belle et al., Cancer 94, 3032 (2002); with granisetron and/or dexamethasone: D. Campos et al., J. Clin. Oncol. 19, 1759 (2001). Clinical pharmacokinetics: A. K. Majumdar et al., J. Clin. Pharmacol. 46, 291 (2006). Review of clinical experience in prevention of chemotherapy-induced nausea and vomiting (CINV): T. M. Dando, C. M. Perry, Drugs 64, 777-794 (2004); A. M. Massaro, K. L. Lenz, Ann. Pharmacother. 39, 77-85 (2005).
Properties: mp 255°. [a]D25 +69° (c = 1.00 in methanol). Sparingly sol in ethanol, isopropyl acetate; slightly sol in acetonitrile. Practically insol in water.
Melting point: mp 255°
Optical Rotation: [a]D25 +69° (c = 1.00 in methanol)
Derivative Type: Fosaprepitant dimeglumine
CAS Registry Number: 265121-04-8; 172673-20-0 (free acid)
CAS Name: 1-Deoxy-1-(methylamino)-D-glucitol [3-[[(2R,3S)-2-[(1R)-1-[bis(trifluoromethyl)phenyl]ethoxy]-3-(4-fluorophenyl)-4-morpholinyl]methyl]-2,5-dihydro-5-oxo-1H-1,2,4-triazol-1-yl]phosphonate (2:1) (salt)
Manufacturers' Codes: MK-0517
Molecular Formula: C23H22F7N4O6P.2C7H17NO5
Molecular Weight: 1004.83
Percent Composition: C 44.23%, H 5.62%, F 13.23%, N 8.36%, O 25.48%, P 3.08%
Literature References: Water-soluble prodrug. Prepn: C. P. Dorn et al., WO 9523798; eidem, US 5691336 (1995, 1997 both to Merck & Co.); J. J. Hale et al., J. Med. Chem. 43, 1234 (2000).
Therap-Cat: Antiemetic.
Keywords: Antiemetic; Neurokinin Receptor Antagonist.
Aprindine Aprinocarsen Aprobarbital Apronalide Aprotinin

Systematic (IUPAC) name
Clinical data
Trade names Emend
AHFS/Drugs.com monograph
MedlinePlus a604003
Pregnancy cat. B1 (AU) B (US)
Legal status Prescription Only (S4) (AU) POM (UK) -only (US)
Routes Oral
Pharmacokinetic data
Bioavailability 60-65%
Protein binding >95%
Metabolism Hepatic (mostly CYP3A4- mediated; some contributions by CYP2C19 & CYP1A2)
Half-life 9-13 hours
Excretion Urine (5%), faeces (86%)
CAS number 170729-80-3 YesY
ATC code A04AD12
PubChem CID 6918365
DrugBank DB00673
ChemSpider 5293568 YesY
ChEBI CHEBI:499361 YesY
Chemical data
Formula C23H21F7N4O3 
Mol. mass 534.427 g/mol
 YesY (what is this?)  (verify)

Aprepitant (brand name: Emend (the brand name used in all English-speaking countries)) is an antiemetic chemical compound that belongs to a class of drugs called substance P antagonists (SPA). It mediates its effect by blocking the neurokinin 1 (NK1) receptor.

Aprepitant is manufactured by Merck & Co. under the brand name Emend for prevention of acute and delayed chemotherapy-induced nausea and vomiting (CINV) and for prevention of postoperative nausea and vomiting. It was approved by the FDA in 2003.[1]

Aprepitant may also be useful in the treatment of cyclic vomiting syndrome & late-stage chemotherapy induced vomiting, but there are few studies to date.

On January 2008, the FDA approved fosaprepitant, an intravenous form of aprepitant, which is to be sold under the tradename Emend Injection in the US and as Ivemend in some other countries.