Potent and selective 5-HT2B/5-HT2C receptor antagonist (rat 5-HT2B pA2 = 8.89, human 5-HT2C pKi = 7.92). Displays > 80-fold selectivity over all other 5-HT receptor subtypes and a variety of other receptors (pKi < 6). Centrally active following oral administration in vivo.