Amitriptyline is a tricyclic antidepressant. Perphenazine is a phenothiazine (feen-oh-THYE-a-zeen). These medicines affect chemicals in the brain that may be unbalanced in people with depression or mental illness. Amitriptyline and perphenazine is a combination medicine used to treat depression, anxiety, and agitation. Amitriptyline and perphenazine may also be used for purposes not listed in this medication guide.