Fig. 1.
Oxycodone metabolism. The major metabolic pathway (bold arrows) of oxycodone is the formation of noroxycodone via CYP3A4 enzymes. Noroxycodone is further metabolised to noroxymorphone via CYP2D6 enzymes. The minor metabolic pathways (narrow arrows) are formation of oxymorphone via CYP2D6 enzymes, and 6-keto reduction to α- and β-oxycodol. Oxymorphone is further metabolised to noroxymorphone via CYP3A4 enzymes