Buy Opana ER 20 mg online, which is an extended release prescription medication containing Oxymorphone. It is used for the management of severe and long term pain when alternative treatments are insufficient. As an opioid, Oxymorphone works by acting on specific receptors on the brain and nervous system, helping to reduce the perception of pain. This affects the central nervous system. It is classified as a scheduled II controlled substance and should only be used under strict medical supervision.