Palonosetron (Aloxi) is a synthetic, potent and selective antagonist of 5-HT3 channel. Palonosetron has an effective concentration of 0.5 nM - 0.5 μM and an IC50 of 0.83±0.49 nM and 0.88±0.15 nM for 5-HT3A and 5-HT3B receptors respectably. Palonosetron is a licensed drug for the prevention and control of emesis in patients undergoing chemotherapy. It is a more effective drug than similar 5-HT3 antagonists with a higher binding affinity due to an allosteric binding site compared to other antagonists (pKi of 10.5 versus an average of 8-9) and an extended half life in vivo. Palonosetron’s unique structural properties suggests its interaction with 5-HT3 is different than granisetron or ondansetron
