MTHFR, Homocysteine and Nitrous Oxide Anesthesia

Mutations in the MTHFR gene cause elevated plasma homocysteine concentrations and have been linked to fatal outcomes after nitrous oxide anesthesia. The most extensively studied gene variant in the homocysteine metabolism is the MTHFR C677T polymorphism, resulting in reduced enzyme activity and, subsequently, in elevated homocysteine.3

One study showed that patients with homozygous or heterozygous MTHFR C677T or A1298C mutations are at a higher risk of developing abnormal plasma homocysteine concentrations after nitrous oxide anesthesia.1

Nitrous oxide is the longest serving member of the anesthesiologist's pharmacologic armamentarium but remains a source of controversy because of fears over its adverse effects. Preclinical reports have suggested that nitrous oxide may contribute to neurocognitive dysfunction in the young and elderly.2