Fesoterodine-d 7 (fumarate) is the deuterium labeled Fesoterodine fumarate. Fesoterodine Fumarate is an orally active, nonsubtype selective, competitive muscarinic receptor ( mAChR ) antagonist with pKi values of 8.0, 7.7, 7.4, 7.3, 7.5 for M1, M2, M3, M4, M5 receptors, respectively. Fesoterodine Fumarate is used for the overactive bladder (OAB).