Bicyclic antidepressant

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.