A tetracyclic antidepressant that inhibits norepinephrine reuptake via the norepinephrine transporter (KD = 11.1 nM); inhibits serotonin 5-HT2A receptors (Ki = 51 nM) and binds the histamine H1 and α1-adrenergic receptors (KD = 2 and 90 nM, respectively.