Detection of Highly Potent Synthetic Opioids in Used Syringes Raises Overdose Concerns

Recent investigations in South Australia have uncovered traces of extremely potent synthetic opioids, specifically nitazenes, in discarded drug paraphernalia such as syringes, plastic bags, vials, and filters found at public needle and syringe program sites. Conducted by researchers from the University of South Australia, this study utilized advanced chemical analysis to identify the presence of nitazenes, which are estimated to be up to 1,000 times more potent than morphine and significantly stronger than fentanyl.

The study analyzed 300 samples, revealing that 5% contained traces of nitazenes. Most of these residues were found in syringes and often in combination with heroin, underscoring the increasing clandestine mixing of dangerous substances in the illicit drug market. Notably, 32 overdose deaths in Australia between 2020 and 2024 have been linked to nitazenes, with the majority of overdose victims unaware they had consumed these potent substances.

Nitazenes' high potency and flexible mixing with other drugs pose serious overdose risks, especially since these substances are often hidden within familiar drugs such as heroin and fentanyl. Lead researcher Associate Professor Cobus Gerber highlighted that some nitazene compounds are even stronger than fentanyl, which is already regarded as highly lethal. The presence of Xylazine, a veterinary sedative not approved for human use, was also detected alongside nitazenes in some samples. Xylazine is associated with severe adverse effects, including skin necrosis, prolonged sedation, and depression.

The detection of these substances is alarming because most users are unaware of their presence. Less than 20% of nitazene-related emergency cases involve individuals who knowingly ingested the drug; others mistake their substances for heroin or methamphetamine. This accidental exposure dramatically narrows the safety margin and increases the likelihood of fatal overdoses.

In light of these findings, there is a growing call for expanded drug-checking initiatives. Rapid chemical testing of used drug paraphernalia can serve as an effective early warning system, alerting health authorities, treatment providers, and community groups about emerging drug threats. Wastewater analysis also plays a role but is less consistent due to the episodic nature of drug use.

Health experts emphasize that public health measures, including drug-checking services and transparent alerts, are essential to reduce overdose fatalities. The study underscores the urgent need for ongoing surveillance and harm reduction strategies to combat the evolving landscape of synthetic opioid misuse.

Source: https://medicalxpress.com/news/2025-08-highly-potent-synthetic-opioids-syringes.html