Pharmaceutical fentanyl is a synthetic opioid pain reliever, approved for treating severe pain, typically advanced cancer pain. It is 50 to 100 times more potent than morphine. It is prescribed in the form of transdermal patches or lozenges and can be diverted for misuse and abuse in the United States.
However, most recent cases of fentanyl-related harm, overdose, and death in the U.S. are linked to illegally made fentanyl analogs, such as acetylfentanyl, furanylfentanyl, and carfentanil, It is sold through illegal drug markets for its heroin-like effect. It is often mixed with heroin and/or cocaine as a combination product—with or without the user’s knowledge—to increase its euphoric effects.