Oxycodone is a pain relief medication. It is a semi-synthetic opioid medication that helps in moderate to severe pain. Buy Oxycodone Online It is available as an immediate-release and extended-release pain formulation for managing pain. How does Oxycodone work? It works by activating your opioid receptors; it works in the CNS and changes the body’s response towards the pain. It is a semi-synthetic opioid, and this medication works in the CNS and changes the brain response toward pain.