Oxycodone 20 mg HCl tablets contain Oxycodone (K 57 grey round pill), a narcotic agonist medication used in adults to manage pain severe enough to require narcotic treatment. It works in the brain to change your body’s emotions and stress response. Oxycodone HCl Controlled-Delivery Tablets are narcotic pain relievers available in 10 mg and 20 mg tablets for oral administration. The pill size indicates how much Oxycodone is in each tablet as the hydrochloride salt.