The Sound of Evolution
Ondansetron
Mechanism of action:
Ondansetron is a selective serotonin 5-HT3 receptor antagonist. Chemotherapy or radiotherapy stimulates enterochromaffin cells in the intestine, causing the release of large amounts of serotonin (5-HT). Serotonin then acts on 5-HT3 receptors on vagal nerve terminals in the gut, transmitting signals to the vomiting center in the medulla and triggering vomiting. Ondansetron works by inhibiting 5-HT3 receptors and blocking this serotonin-mediated emetic reflex pathway.
Reference(s):
1. Ramsook C et al. (2002). A randomized clinical trial comparing oral ondansetron with placebo in children with vomiting from acute gastroenteritis. Ann Emerg Med.
2. Yilmaz HL et al. (2010). Clinical trial: oral ondansetron for reducing vomiting secondary to acute gastroenteritis in children--a double-blind randomized study. Aliment Pharmacol Ther.