Oxymorphone (Opana, Numorphan, Numorphone) or 14-Hydroxydihydromorphinone is a powerful semi-synthetic opioid analgesic (painkiller) first developed in Germany in 1914, patented in the USA by Endo Pharmaceuticals in 1955 and introduced to the United States market in January 1959 and other countries around the same time.

Oxymorphone (Opana, Numorphan, Numorphone) or 14-Hydroxydihydromorphinone is a powerful semi-synthetic opioid analgesic (painkiller) first developed in Germany in 1914, patented in the USA by Endo Pharmaceuticals in 1955 and introduced to the United States market in January 1959 and other countries around the same time.