SB-200646A is the first selective 5-HT2B/2C over 5-HT2A receptor antagonist with pKi values of 7.5, 6.9 and 5.2 for 5-HT2B, 5-HT2C and 5-HT2A, respectively. SB-200646A is orally active and has electrophysiological and anxiolytic properties in vivo[1][2].