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BMJ neurology open
Published

Recreational nitrous oxide and thrombotic events: a case series

Authors

Marta Patyjewicz, Devan Mair, Safiya A Zaloum, Barbara Onen, Joseph Walton, Ruth Dobson, Christine Joerres, Apeksha Madhusudan Shah, Peter MacCallum, Thomas H Massey, Tadbir Bariana, Veronica White, Sarah A De Freitas, Alastair Noyce

Abstract

BMJ Neurol Open. 2024 May 15;6(1):e000619. doi: 10.1136/bmjno-2023-000619. eCollection 2024.

ABSTRACT

BACKGROUND: The study aimed to elucidate the prevalence of nitrous oxide (N2O) usage in patients with unexplained venous thromboembolism (VTE), highlighting the potential association with hyperhomocysteinaemia (HHcy).

METHODS: We conducted a retrospective study at the Royal London Hospital, examining cases of N2O-related VTE from March to August 2023. Among 50 patients identified, four (8%) had recent unprovoked VTE. Patient data were collected based on N2O ambulatory emergency care pathway admissions.

RESULTS: Among the 50 patients identified, four (8%) had recent or concurrent VTE. Three were male (75%), with an ethnic distribution of 50% Asian or Asian British and 50% Black or Black British. Patients were distributed across quintiles of the index of multiple deprivation. All had actual or functional vitamin B12 deficiency.

DISCUSSION: The association between N2O use and VTE requires further investigation, though a plausible mechanism involving HHcy has been proposed. Clinicians should be vigilant for VTE in N2O users, especially those presenting with unexplained symptoms. VTE prophylaxis may be worth considering, particularly if continued exposure to nitrous oxide is anticipated.

CONCLUSION: N2O misuse may increase the risk of VTE, warranting attention from healthcare providers. Further research is needed to elucidate this association and inform preventive strategies. Public awareness about the risks of N2O remains essential.

PMID:38757110 | PMC:PMC11097798 | DOI:10.1136/bmjno-2023-000619