https://healthetive.com/product/opana-er-15-mg/ 

         
           Generic name: Oxymorphone [ OX-ee-MOR-fone ] 

           Brand names: Opana, Opana ER. 

           Drug class: Opioids (narcotic analgesics)

        Opana ER 15 mg {Oxymorphone} is a congener of morphine with a substitution of a ketone group at the C-6 position, conferring a more rapid onset of action, greater potency, and a slightly longer duration of action than morphine. Oxymorphone was more potent than the comparator opioids on several measures, including drug liking and respiratory depression (p < 0.05). Across abuse-related subjective outcomes, oxymorphone was 2.3-2.8-fold more potent than hydromorphone and 12.5-14-fold more potent than oxycodone (p < 0.05).