Department of Health

Cocaine adulterated with protonitazene

A white powder sold in Melbourne as cocaine contains the potent opioid 'protonitazene'.

Protonitazene is a novel synthetic opioid that can produce life-threatening toxic effects in very small amounts

Opioids are central nervous system depressants, typically producing a range of effects including pain relief, sedation and respiratory depression (dangerously slow breathing). Respiratory depression often appears more quickly with novel synthetic opioids (NSOs), increasing the risk of life-threatening overdose.

Protonitazene is an extremely potent NSO, which means it can produce strong effects in very small amounts. Protonitazene has a potency over 100 times that of heroin.

Cocaine and protonitazene are very different substances. Cocaine produces stimulant effects, whereas protonitazene produces sedative effects and may lead to opioid overdose. Using protonitazene with depressants such as alcohol, GHB or depressant drugs (such as Xanax or Valium) increases the risk of overdose.

Know the signs of opioid overdose and carry naloxone

There have been recent serious harms in Melbourne associated with a white powder sold as cocaine that contained protonitazene. The product appears to produce strong adverse effects such as loss of consciousness, respiratory depression, and life-threatening hypoxia (insufficient oxygen for normal functioning).

Signs of opioid overdose include breathing slowly and reduced consciousness (meaning someone is hard to wake up). In some cases, there may also be tiny pupils. More information about opioid overdose symptoms can be found on the Penington Institute websiteExternal Link .

Naloxone is an easy-to-use medication that can reverse opioid overdose – it is safe to use even if you are not sure whether someone has taken opioids. Naloxone can be accessed free of charge at participating pharmacies, needle and syringe programs and the medically supervised injecting centre. You can find an approved naloxone provider on the Take Home Naloxone program webpage.

Reduce the risk of harm

If you experience toxic drug effects, or are present when someone has an unexpected reaction, seek help immediately by calling Triple Zero (000).

All alcohol and other drug use comes with risks, so take the following precautions:

  • Be aware that other false or contaminated drug products may circulate in Victoria, even if no specific warning has been issued about them.
  • Get free naloxone and carry it with you – no matter what drugs you think you’re getting.
  • Make sure you’re in a safe environment with people you trust.
  • Remember, even ‘pure’ drugs can produce serious side effects and death, and can interact dangerously with medications/pharmaceutical drugs. Get the facts on the Alcohol and Drug Foundation websiteExternal Link .

Contact Harm Reduction Victoria’s DanceWize team for anonymous support and education from peers. Talk to DanceWize volunteers by email at

If you or someone you know needs help with alcohol or drug use, call DirectLine on 1800 888 236 or visit DirectLineExternal Link for information and support to access treatment.


Reviewed 01 July 2024


Was this page helpful?