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Systematic (IUPAC) name
CAS number 122852-42-0
ATC code A03AE01
PubChem 2099
DrugBank APRD00580
Chemical data
Formula C17H18N4O 
Mol. mass 294.351 g/mol
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%
Therapeutic considerations
Pregnancy cat.

B (U.S.)

Legal status

℞-only (U.S.)

Routes Oral

Alosetron is a 5-HT3 antagonist used for the management of severe diarrhoea-predominant irritable bowel syndrome (IBS) in women only. It was withdrawn from the market in 2000 owing to the occurrence of serious life-threatening gastrointestinal adverse effects, but was reintroduced in 2002 with availability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. It is currently marketed by GlaxoSmithKline under the trade name Lotronex.


Mode of action

Alosetron, while being a 5-HT3 antagonist like ondansetron, is not an antiemetic. Alosetron has an antagonist action on the 5-HT3 receptors of the enteric nervous system of the gastrointestinal tract.

Serious adverse effects

Alosetron was withdrawn in 2000 following the association of alosetron with serious life-threatening gastrointestinal adverse effects.

The cumulative incidence of ischaemic colitis was 2 in 1000, while serious complications arising from constipation (obstruction, perforation, impaction, toxic megacolon, secondary colonic ischaemia, death) was 1 in 1000.[1]


  1. ^ GlaxoSmithKline plc. Lotronex (U.S. Prescribing Information). Brentford: GlaxoSmithKline; 2002.

See also

  • Irritable bowel syndrome
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Alosetron". A list of authors is available in Wikipedia.
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