Cymbalta is a serotonin and norepinephrine reuptake inhibitor (SNRI) indicated for:

• Major Depressive Disorder (MDD) (The efficacy of Cymbalta was established in four short term and one maintenance trial in adults)
• Generalized Anxiety Disorder (GAD) (The efficacy of Cymbalta was established in three short-term trials and one maintenance trial in adults)
• Management of Neuropathic Pain (DPNP) associated with diabetic peripheral neuropathy
• Fibromyalgia (FM)
• Chronic Musculoskeletal Pain (This has been established in studies in patients with chronic low back pain and chronic pain due to osteoarthritis)  
• Osteoarthritis  

Cymbalta treats these conditions by increasing the levels of serotonin and norepinephrine in the brain, two neurotransmitter chemicals that play an important role in maintaining mood and pain signals in the brain.