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 It was withdrawn from the market in 2000 owing to the occurrence of serious life-threatening gastrointestinal adverse effects, but was reintroduced in 2002 with availability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Alosetron was withdrawn in 2000 following the association of alosetron with serious life-threatening gastrointestinal adverse effects.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 (GlaxoSmithKline, 2002).

References

• GlaxoSmithKline (2002). Lotronex Prescribing Information. (U.S. edition) Brentford: GlaxoSmithKline