Near death from a novel synthetic opioid labeled U-47700: emergence of a new opioid class

In the last decade there has been a worldwide surge in the recreational abuse of novel psychoactive substances, particularly amphetamine derivatives and synthetic cannabinoids. Synthetic opioids such as AH-7921, MT-45, and U-47700, with structures distinct from those ever used therapeutically or described recreationally, have also recently emerged.