buy Oxynorm 20mg Oxycodone, which is sold under the Oxynorm brand , is an opioid drug used to treat moderate to severe pain and a common addictive drug.   It is usually taken orally and is available in immediate release and controlled release formulations.  The onset of pain relief usually begins within 15 minutes and lasts for up to six hours with the immediate release formulation.  In the UK, it is available by injection.  Combination products are also available with paracetamol (acetaminophen), ibuprofen, naloxone and aspirin.