Title: Alosetron
CAS Registry Number: 122852-42-0
CAS Name: 2,3,4,5-Tetrahydro-5-methyl-2-[(5-methyl-1H-imidazol-4-yl)methyl]-1H-pyrido[4,3-b]indol-1-one
Manufacturers' Codes: GR-68755
Molecular Formula: C17H18N4O
Molecular Weight: 294.35
Percent Composition: C 69.37%, H 6.16%, N 19.03%, O 5.44%
Literature References: Serotonin 5HT3-receptor antagonist. Prepn: I. H. Coates et al., EP 306323; eidem, US 5360800 (1989, 1994 both to Glaxo); of isotopically labelled compd: S. R. Prakash et al., J. Labelled Compd. Radiopharm. 36, 993 (1995). HPLC determn in plasma: T. L. Lloyd et al., J. Chromatogr. B 678, 261 (1996). Review of clinical pharmacology: M. D. Gunput, Aliment. Pharmacol. Ther. 13, Suppl. 2, 70-76 (1999); of clinical studies: A. W. Mangel, A. R. Northcutt, ibid. 77-82. Clinical trial in irritable bowel syndrome: M. Camilleri et al., Lancet 355, 1035 (2000).
Derivative Type: Hydrochloride
CAS Registry Number: 122852-69-1
Manufacturers' Codes: GR-68755C
Trademarks: Lotronex (GSK)
Molecular Formula: C17H18N4O.HCl
Molecular Weight: 330.81
Percent Composition: C 61.72%, H 5.79%, N 16.94%, O 4.84%, Cl 10.72%
Properties: mp 288-291°.
Melting point: mp 288-291°
Therap-Cat: In treatment of irritable bowel syndrome.
Keywords: Serotonin Receptor Antagonist.
Aloxidone Aloxiprin alpha-(alpha-Aminopropyl)benzyl Alcohol alpha,alpha,beta-Trichloro-n-butyraldehyde alpha1-Antitrypsin

Systematic (IUPAC) name
Clinical data
Trade names Lotronex
AHFS/ monograph
MedlinePlus a601230
Pregnancy cat. B (U.S.)
Legal status ℞-only (U.S.)
Routes Oral
Pharmacokinetic data
Bioavailability 50–60%
Protein binding 82%
Metabolism Hepatic (including CYP2C9, CYP3A4 and CYP1A2)
Half-life 1.5–1.7 hours
Excretion Renal 73%, faecal 24%
CAS number 122852-42-0 YesY
ATC code A03AE01
PubChem CID 2099
IUPHAR ligand 2296
DrugBank DB00969
ChemSpider 2015 YesY
UNII 13Z9HTH115 YesY
KEGG D07129 YesY
ChEBI CHEBI:253342 YesY
Chemical data
Formula C17H18N4O 
Mol. mass 294.351 g/mol
 YesY (what is this?)  (verify)

Alosetron hydrochloride (initial brand name: Lotronex; originator: GSK) is a 5-HT3 antagonist used for the management of severe diarrhea-predominant irritable bowel syndrome (IBS) in women only. It is currently marketed by Prometheus Laboratories Inc. (San Diego), also under the trade name Lotronex. Alosetron was withdrawn from the market in 2000 owing to the occurrence of serious life-threatening gastrointestinal adverse effects, but was reintroduced in 2002 with availability and use restricted.