Oxycodone 30mg is used to treat severe chronic pain (such as due to cancer). Oxycodone belongs to the opioid analgesics class of drugs. It changes how your body feels and responds to pain by acting on the brain. The higher strengths of this drug (more than 40 milligrams per tablet) should be used only if you have been taking moderate to high doses of an opioid pain medication on a regular basis.