Nitrous Oxide Is No Laughing Matter

According to a new review, the recreational use of nitrous oxide can have serious and sometimes permanent neurological impacts. Although this drug is becoming increasingly popular, the findings are worrying. It is hoped the results of the survey will help doctors identify the signs of nitrous oxide toxicity.

Nitrous oxide (N2O), also known as laughing gas, is a colorless, odorless, and non-flammable gas. It was first used therapeutically in 1844 for dental surgery and has remained one of the most commonly used anesthetic agents ever since. This is because it is pretty mild as anesthetics go, making it valuable for minor medical or dental procedures. In recent years, however, the gas has also become popular for recreational use, where it can be inhaled to achieve a short-lived but nearly instantaneous high.

According to the 2021 Global Drug Survey, around 23 percent of all respondents indicated they had used the drug at some point, and nearly 10 percent in the previous year alone. Increasingly, the drug is becoming a concern in many jurisdictions across the world, including Canada, Australia, parts of Europe, and especially the UK. Part of the issue here is that the drug and its accompanying paraphernalia are easily ordered online. It’s cheap, it’s quick, and it's often thought to be safer compared to other drugs.

“The low cost of and ease of access to nitrous oxide make it a popular recreational drug, especially among younger people,” Dr Cyrille De Halleux, a specialist in internal medicine, critical care and resident at The Hospital for Sick Children (SickKids) and chief fellow in the Division of Clinical Pharmacology and Toxicology at the University of Toronto, Toronto, Ontario, writes in the review.

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But despite the feelings of euphoria and floating associated with the high, frequent use of nitrous oxide can also have significant negative impacts. In particular, chronic use can cause functional vitamin B12 deficiency, which can result in long-term issues, especially neurological ones.

The new review of the existing literature found three common disorders associated with its use. These include damage to the spinal cord (myelopathy), nerve damage affecting strength and sensation (neuropathy), and behavioral abnormalities (encephalopathy).

Generally speaking, the main treatment for nitrous oxide toxicity is the cessation of use, but vitamin B12 supplements can also be provided along with methionine (however, the evidence for its efficacy is sparse).

“Clinicians should enquire about nitrous oxide use in patients with unexplained findings suggestive of vitamin B12 deficiency or other compatible neurologic symptoms,” the authors conclude.

The review is published in the Canadian Medical Association Journal.