A New Zealander in their early 20s was hospitalised for almost 30 days after consuming 720 nitrous oxide canisters in 24 hours, a new study has revealed. 

Known on the streets as ‘nangs’ or ‘nos’, nitrous oxide has been used as a sedative for pain relief for more than 150 years, but it’s also abused as a recreational drug. 

A study published in today’s New Zealand Medical Journal looks at the effect excessive nitrous oxide usage had on 12 patients, aged 16 to 50, who were admitted to hospital between 2016 and 2023. 

One patient, aged between 21 and 25, spent 26 days in hospital after consuming 720 canisters of nitrous oxide in a single day. 

Another severely affected patient presented with quadriparesis, a condition in which you have muscle weakness in all four limbs. 

Medical experts have warned of the effects of excessive consumption of 'nangs' or nitrous oxide canisters. Photo / Andrew Warner 

That person spent 56 days in hospital after consuming 200 canisters in a single session for the first time in their life. 

Further results of the study concluded: 

- Five patients reported lower limb weakness, including one who also had upper limb weakness. 

- Five had changes in mental state, including three with poor concentration and one with psychosis. 

- The longest period a patient spent in hospital was 56 days and the shortest was two days. 

- Three patients required ongoing support for activities of daily living. 

- All 12 patients were offered counselling support and ceased nitrous oxide use. 

“This case series highlights the dangers of inhaled nitrous oxide, with patients presenting with cognitive, psychiatric and neurological impairment,” the study read. 

“The prevalent recreational use of nitrous oxide underscores the need to improve education and restrict access to this drug.” 

'Nangs' are most commonly sold in boxes of 10. 

The study said four patients with a peak daily usage of more than 100 canisters were aware of potential dangers and were taking over-the-counter vitamin B12. 

“It suggests that patients who self-supplement vitamin B12 may tolerate very large quantities of nitrous oxide before experiencing symptoms.” 

But the supplements did not prevent the patients from showing signs of developing myelopathy - an injury to the spinal cord. 

The New Zealand Medical Journal study suggested public health intervention to discourage people from using nitrous oxide recreationally, specifically restricting sales from commercial vendors. 

A spokesperson for the Ministry of Health last year told the Herald it was illegal to supply nitrous oxide for inhalation without a prescription and retailers supplying recreational users of the drug “bear a responsibility” for the harm it may cause. 

They said Medsafe “strongly” advised against the recreational use of nitrous oxide, saying it can have “serious physical effects on the lungs and mouth, can interact with other taken medicines or drugs and can lead to other medical issues with prolonged use”. 

Benjamin Plummer is an Auckland-based reporter who covers breaking news. He has worked for the Herald since 2022.