A tetracyclic antidepressant that inhibits norepinephrine and serotonin reuptake, binding the respective transporters with Kd values of 16 and 58 nM; acts as either an antagonist or inverse agonist at 5-HT2A, 2B, 2C, 3, 6, 7 (Kis = 1 and 2 nM for 5-HT2A and 5-HT2C), D2, 3, 4 (Kd = 160 nM for D2), α1-adrenergic (Kd = 50 nM), and H1 (Kd = 25 nM) receptors.