Oxycodone is a prescription opioid pain reliever used to treat moderate to severe pain. It works by altering the brain's perception of pain and is often prescribed following surgery, injury, or for chronic pain conditions. Oxycodone belongs to a class of drugs known as opioid analgesics. It works in the brain to change the way your body feels and reacts to pain. This medication has been prescribed to relieve moderate to severe pain for 12 hours.