Opioids are a class of drugs naturally found in the opium poppy plant and that work in the brain to produce a variety of effects, including the relief of pain with many of these drugs. Opioids can be prescription medications often referred to as painkillers, or they can be so-called street drugs, such as heroin.
Fentanyl is a synthetic opioid that is up to 50 times stronger than heroin and 100 times stronger than morphine. It is a major contributor to fatal and nonfatal overdoses in the U.S.
Source Credit: Centers for Disease Control, Fentanyl Facts