OxyContin is a prescription opioid pain medication used to treat moderate to severe pain. It is an extended-release form of oxycodone, which is an opioid that works by changing the way the brain and nervous system respond to pain. OxyContin is usually taken orally every 12 hours, but it can also be taken every 8 hours for more severe pain. OxyContin can be habit-forming and should only be used as prescribed by a doctor.