Fentanyl is a powerful synthetic opioid, a respiratory depressant that can restrict the user's ability to breathe. Created in the 1960s to manage pain after surgery, clinical use expanded in the 1990s with the extended release patch for chronic pain, typically caused by cancer. The pain relief is immediate.
Fentanyl is now illicitly made in labs and sold as powder or tablets or mixed with a variety of drugs such as heroin, cocaine and methamphetamine. It is cheap and easy to produce and is ten times more likely to cause an overdose than other opioids.
Huge quantities of fentanyl from China are smuggled into the United States through Mexico. In the last year, 900,000 Americans overdosed on drugs and died. About half of those deaths involved fentanyl.