Cymbalta is a selective serotonin and norepinephrine reuptake inhibitor (SSNRI) which is prescribed to treat major depressive disorder (MDD) and generalized anxiety disorder (GAD). Cymbalta is also known by the generic name duloxetine. In addition to its use as an antidepressant, Cymbalta may be prescribed to treat diabetic neuropathy (nerve pain caused by diabetes), chronic muscle or joint pain, and fibromyalgia.