Neuropathic pain (NP), caused by a primary lesion or dysfunction in the nervous system, affects approximately 4 million people in the United States each year. It is associated with many diseases, including diabetic peripheral neuropathy, postherpetic neuralgia, human immunodeficiency virus-related disorders, and chronic radiculopathy. Major pathophysiological mechanisms include peripheral sensitization, sympathetic activation, disinhibition, and central sensitization. Unlike most acute pain conditions, NP is extremely difficult to treat successfully with conventional analgesics.
