Mirtazapine is called a tetracyclic antidepressant, much as Pamelor, aka nortriptyline HCl, is called a tricyclic antidepressant
I take nortriptyline, too, but one of its side effects combined with not eating enough fiber started the problems to the point I refused to take as much as they wanted me to.
The tricyclics seem to be the only ones I can tolerate now. Thanks for your knowledgeable response.
And Effexor and a few others are considered bicyclic antidepressants, otherwise known as Lance Armstrong antidepressants.