Oxycodone HCl + Naloxone HCl is a combination drug for pain relief. It binds to kappa, mu, and delta opiate receptors that are located in the brain, spinal cord and other organs such as those in the digestive system. Oxycodone is a drug that is known as an opioid receptor agonist that acts on these receptors, bringing about relief from pain by binding to the endogenous opioid receptors in the brain and spinal cord. On the other hand, naloxone is a true antagonist that acts on all opioid receptors. The two drugs have synergistic effects.