Chronic nitrous oxide use inactivates vitamin B12, causing neurological and psychiatric damage. A case series from an Australian emergency department between 2019 and 2021 identified 22 patients, mostly young males (median age 22.4 years), who inhaled a median of 150 bulbs daily for 9 months. Common symptoms included ataxia, numbness, falls, urinary retention, and psychosis; 12 of 14 patients who underwent MRI had spinal cord degeneration. All received vitamin B12 injections, and many also oral methionine. Hospital stays lasted a median of 4 days, costing about $2,061 per day. The data prompted public health measures such as warning labels, purchase limits, and legal restrictions on sales intended for abuse.
From 2021 to 2023, Australians who regularly used ecstasy or other stimulants and also used nitrous oxide showed a rise in use of large cylinders (from 6% to 26%) and a rise in reported neurological symptoms (from 5% to 14%). Most respondents knew about brain or nerve damage risks, but only one in five identified vitamin B12 depletion as a risk, and 17% were unaware of any risks. One-third took no precautions. Sourcing from convenience stores and 24/7 delivery services was common and linked to heavier use. Fewer than five people received treatment for symptoms. The authors call for balanced regulation and education of retailers, clinicians, and consumers.