Over time, prescription opioids became harder to get legally, mostly because of efforts to crackdown on excessive prescribing and enhanced law enforcement efforts. Looking for alternatives, or cheaper options, some turned to heroin or black market fentanyl.

Fentanyl is a power anesthetic — 30 to 50 times more potent than heroin and 50 to 100 times more potent than morphine — used by patients to relieve severe chronic pain.

Over the past few years, however, it has been manufactured illicitly and sold on the streets.

From 2010 to 2015, annual overdose deaths involving opioids increased nearly 57 percent, largely due to the spike in use of fentanyl and other synthetic opioids.