Oxycodone is a pain reliever that is used to relieve different types of pain. Oxycodone is an opioid and this classifies it as being a narcotic drug. Oxycodone extended-release is used in a course of pain treatment that requires around the clock pain relief for a patient. The mechanism of action for Oxycodone is not that known. However, it is thought that, it does involve the stimulation of opioid receptors that are in the brain.