It's killed tens of thousands of people in the United States and now it's been revealed doctors in New Zealand are prescribing the powerful painkiller, fentanyl, at twice the rate they were five years ago.
A coroner linked the controversial drug to the death of a 24-year-old in Whanganui today after he suffered a shoulder injury in a quad bike accident last year.
Chairman of the Health Quality and Safety Commission's opioid expert advisory group, Doctor Alan Davis told 1 NEWS fentanyl is a "very potent drug".
"It's 25 to 50 times the potency of morphine," Dr Davis said.
The Health Quality and Safety Commission found that for every 1,000 people, two are using fentanyl.
"I'm not surprised but it is something we want to keep a very close eye on and particularly understand why it is being used in such a variable way."
Overall, the number of people who are using strong opioids is on the rise.
Last year 77,000 people were given sign off by their doctor to use the likes of methadone and morphine which is up from 63,000 in 2011.
Northland, Bay of Plenty, Whanganui and Wairarapa have the highest per capita dispensing of strong opioids with the use of fentanyl in Bay of Plenty and Whanganui about twice as high as in most other regions.
"As with any opiate the main concern is that it suppresses breathing so if you have too much of it you will simply stop breathing and you'll die so the danger is overdose," Know Your Stuff Campaigner Wendy Allision told 1 NEWS.
Wendy Allison tests recreational drugs to make sure users know exactly what they're taking and she's worried about what she will find at this year's summer music festivals.
"If they're being prescribed by doctors, they're being diverted into the illicit market," she said.
The Health Quality and Safety Commission wants to work with district health boards to understand why doctors are prescribing more of these dangerous drugs and to ensure public safety is bring put first.