Opioid agonists are substances that bind to opioid receptors in the brain and body, mimicking the effects of natural pain-relieving chemicals. They are commonly used to manage pain and can produce feelings of euphoria, relaxation, and sedation. Examples of opioid agonists include morphine, oxycodone, and fentanyl. These medications work by blocking pain signals and altering the perception of pain. While they can be effective for treating severe pain, they also carry a risk of addiction and dependence. Therefore, they are typically prescribed with caution and monitored closely by healthcare professionals.