Opana ER (extended-release) 40mg is a potent opioid medication prescribed for the management of severe pain that necessitates continuous, around-the-clock treatment. Each tablet contains oxymorphone, a powerful analgesic that acts on the central nervous system to alleviate pain. This medication is typically reserved for patients who have not achieved adequate pain relief with other less potent opioids or non-opioid analgesics.