A first generation tricyclic antidepressant that acts primarily as an inhibitor of serotonin and norepinephrine transporters (Kds = 1.4 and 37 nM, respectively); an antagonist at histamine, muscarinic acetylcholine, and α1-adrenergic receptors (Kd values are 37, 46, and 32 nM for H1, M1, and α1, respectively)