Bicyclic antidepressants are a class of
antidepressant drugs. They are named after the drugs'
molecular structure, which contains two rings of atoms
(compare
tetracyclic and
tricyclic antidepressants). The term 'bicyclic
antidepressant' is of lesser usage than the terms tricyclic
or tetracyclic subtypes since for most bicyclic structured
antidepressant drugs their pharmacological identity is
largely defined not by their structure but their mode of
action. An example of this is Fluoxetine, though structurally bicyclic, is categorized
among
selective serotonin reuptake inhibitors.