Opioids are typically used to treat chronic pain that's moderate to severe. But they also have some other uses. They work by binding to specific receptors in your brain and spinal cord to reduce the perception of pain. These medications come in different forms, including oral pills, extended-release tablets, and injectable solutions. Examples include tramadol (ConZip), oxycodone (Roxicodone, Oxycontin), and morphine extended-release (MS Contin). And methadone (Methadose) is an opioid that treats opioid use disorder, as well as chronic pain..