Narcotic analgesics are a class of medicines that are used to provide relief from moderate-to-severe acute or chronic pain.Narcotic analgesics are one of the most widely used analgesics for pain relief; however, they have been overused, overprescribed, and misused which has resulted in more than two million people in the U.S. alone having a substance misuse disorder involving prescription narcotic analgesics.The main opioid receptor that narcotic analgesics bind to is the mu receptor.