Oxymorphone (
Opana,
Numorphan,
Numorphone) or 14-Hydroxydihydro
morphinone 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.