Isotonitazene


Isotonitazene is a benzimidazole derived opioid analgesic drug related to etonitazene, which has been sold as a designer drug. It has only around half the potency of etonitazene in animal studies, but it is likely less potent in humans as was seen with Etonitazene.
Isotonitazene was fully characterized in November 2019 in a paper where the authors performed a full analytical structure elucidation in addition to determination of the potency at the μ-opioid receptor using a biological functional assay in vitro. While isotonitazene was not compared directly to morphine in this assay, it was found to be around 2.5x more potent than hydromorphone and slightly more potent than fentanyl.

Side effects

Side effects of benzimidazole derived opioids are expected to be similar to those of fentanyl, which include itching, nausea and potentially serious respiratory depression, which can be life-threatening.
Isotonitazene has been detected in multiple fatalities in the US since August 2019.

Legal status

The US Drug Enforcement Administration issued a notice of intent to publish a temporary order to schedule isotonitazene in Schedule I of the Controlled Substances Act.