Department of Health, Victoria issued a drug alert on 03 May 2025, regarding the detection of metonitazene in powder sold as ketamine.
Metonitazene is a PSO. Its potency is similar to fentanyl, estimated to be between 30 and 200 times that of morphine. This means very small amounts can produce life-threatening toxic effects such as loss of consciousness, respiratory depression and hypoxia (insufficient oxygen for normal functioning).
Be cautious about any powder with a white-brown colour or tinge, especially if sold as ketamine or heroin
Two people in Melbourne were recently exposed to metonitazene after using a powder sold as ketamine. The substance was described as ‘white-brown and chunky’, but easily crumbled into a powder. Blood testing also showed evidence of heroin and it is possible that this substance could be sold as heroin.
People who are expecting to use ketamine may not know how to recognise and respond to opioid overdose. Someone might appear to be entering a ‘K-Hole’ (a dissociative state brought on by higher doses of ketamine) but could actually be showing signs of opioid overdose. Signs of opioid overdose to look out for include: breathing slowly, reduced consciousness (meaning someone is hard to rouse or wake), and tiny pupils in some cases. More information about opioid overdose symptoms can be found on the Penington Institute .
Using metonitazene or other opioids with depressants such as alcohol, GHB or benzodiazepines (‘Xanax’, ‘Valium’, ‘Mylan’, etc) increases the risk of overdose.
Reduce the risk of harm and get naloxone to reverse opioid overdose
If you experience adverse drug effects, or are present when someone has an unexpected reaction, seek help immediately by calling Triple Zero (000).
