If you have fibromyalgia, depression, neuropathic pain, or generalized anxiety disorder, a healthcare provider may prescribe Cymbalta^® (duloxetine hydrochloride). Depression and anxiety are caused when the levels of certain chemicals in the brain (serotonin and norepinephrine) become unbalanced. Cymbalta helps block the reuptake of norepinephrine and serotonin to help keep the chemicals more balanced. Although it is not entirely clear as to how Cymbalta works for nerve pain, it appears that Cymbalta helps block the nerve pain signals in the spinal cord or brain. As with any medication, it is possible to overdose on Cymbalta. Seek immediate medical attention if you develop any overdose symptoms, such as seizures, hallucinations, or difficulty walking.