Oxycodone hydrochloride is thoroughly metabolized to noroxycodone, oxymorphone, and their glucuronides. The most important circulating metabolite is noroxycodone having an AUC ratio of 0. The main circulating metabolite is noroxycodone having an AUC ratio of 0.six relative to that of oxycodone. Oxymorphone is present in the plasma only in very l