A warning has been issued after a series of severe opioid overdoses occurred in Sydney's west last month.
Nitazenes, potent synthetic opioids, have been found in a cluster of 20 overdoses reported in the Nepean Blue Mountains Local Health District
The synthetic drug can be stronger than fentanyl and 100 times more potent than heroin, according to NSW Health.
Nitazenes are also more likely to stop or slow down breathing.
"Nitazenes are extremely potent," NSW Health Chief Addiction Medicine Specialist Dr Hester Wilson said.
"It is important that people recognise the signs of an opioid overdose early and know how to respond.
"Opioids such as heroin can cause pin-point pupils, drowsiness, loss of consciousness, slowed breathing/snoring and skin turning blue/grey and can be life-threatening.
"One of the dangers of illicit drug supply is the strength and contents of the substance you are getting is unknown and can be inconsistent.
"In light of this detection, people who use drugs such as heroin should carry naloxone."
Investigations into the overdose cases are ongoing.
NSW Health recommends take-home naloxone as a life-saving measure as it can temporarily reverse an opioid overdose.
For more information visit NSW Health
