A selective 5-HT3 receptor antagonist (IC50s = 0.36-1.3 μM for human 5-HT3A, 5-HT3AB, 5-HT3AC, and 5-HT3AE in a FLIPR membrane potential assay); selective for 5-HT3 over other Cys-loop containing receptors (IC50 values >100 μM for mouse, rat, and human nAChRs, human GABAARs, and human GlyRs; inhibits 5-HT-induced currents in COS-7 cells expressing human 5-HT3A (IC50 = 0.49 μM); reduces growth of HepG2 cells in a dose-dependent manner ,