Metonitazene is an analgesic compound related to etonitazene, which was first reported in 1957. It has been shown to have approximately 1000 times the potency of morphine by central routes of administration, but if used orally it has been shown to have the approximately 10 times the potency of morphine.
Its effects are similar to other opioids such as fentanyl and heroin, including analgesia, euphoria, and sleepiness. Adverse effects include vomiting, and respiratory depression that can potentially be fatal. It is commonly used in the illicit manufacture of counterfeit-OxyContin opioid pills.