Oxycodone 20 mg is an opioid painkiller for treating moderate to severe pain. It works by binding to opioid receptors in your brain that help reduce pain perception. When you take Oxycodone medicines , it enters your bloodstream and travels to your brain and spinal cord. There, it attaches to opioid receptors. Also, blocks pain signals, which helps relieve pain and improve the ability to function. The effects tend to last for around 6 hours.