Generic Oxycontin is used to relieve severe pain. GenericOxycontin is in a class of medications called opiate (narcotic) analgesics. It works by changing the way the brain and nervous system respond to pain.It is primarily used for chronic, moderate to severe pain, such as: Pain from cancer, Pain after major surgery, Other long-term pain conditions when non-opioid medications or immediate-release opioids have not worked.