Many patients who were prescribed opioids start with oxycodone. As a person’s tolerance increases over time, they may begin using stronger opioids, such as heroin, a highly addictive drug made from morphine. An even more potent opioid is fentanyl — according to the federal Centers for Disease Control and Prevention, fentanyl is up to 50 times stronger than heroin and 100 times stronger than morphine.Learn about the risks of being exposed to fentanyl