Nitrous oxide is an increasingly popular recreational drug. However
recurrent or prolonged use can be associated with nitrous oxide
toxicity, with numerous reports of harm documented in the literature.
Nitrous oxide irreversibly binds and inactivates vitamin B12, which is
an important co-factor in metabolic pathways involved in DNA and myelin
synthesis. Toxicity is therefore associated with vitamin B12
deficiency-related syndromes, primarily involving haematological and
neurological systems. As a ‘legal high’, nitrous oxide use has attracted
repeated health warnings from experts. An awareness and understanding of
the pathophysiology and management of nitrous oxide toxicity is
therefore important for clinicians. We discuss the case of a 29-year old
man presenting with nitrous oxide-induced sensorimotor neuropathy and
review the existing literature surrounding toxicity.