Homocysteine After Nitrous Oxide Anesthesia

Anesthesia, General Clinical Trial

Official title: Influence of the MTHFR 677C>T Mutation on Homocysteine Levels After Nitrous Oxide Anesthesia.

Status Completed

Clinical Trial Summary

Our study looks at the interaction of a common mutation in the MTHFR gene and the risk of developing higher homocysteine levels after nitrous oxide (N2O) anesthesia.

Specifically, we want to test the hypothesis that healthy patients carrying the MTHFR 677C>T haplotype develop abnormal homocysteine levels after nitrous oxide anesthesia.

Clinical Trial Description

Nitrous oxide – laughing gas – is a widely used anaesthetic gas with many favourable but also some dangerous properties. Among the latter is the increase in homocysteine levels after nitrous oxide (N2O) exposure by inhibition of enzymes in the vitamin B12 pathway. Elevated homocysteine levels have been found to be an independent risk factor for ischemic events and are associated with an increased risk for perioperative myocardial ischemia. If a patient carries one or more loss-of-function mutations in enzymes of the methionine/homocysteine/folate pathway he is at an increased risk for hyperhomocysteinemia and if exposed to N2O might suffer severe, sometimes disastrous neurological damage. Recently, a case report in the New England Journal of Medicine reported the death of a child with an enzyme defect in the MTHFR gene after anaesthesia with nitrous oxide (NEJM 2003;349:45-50).

Thus, we are convinced that if we can determine the risk of patients who carry mutations in the MTHFR gene and undergo anaesthesia with N2O for developing pathological levels of homocysteine, we can add an important piece of information to the safety profile of N2O.

Our study tests the hypothesis that patients who carry the 677C<T mutation in the MTHFR gene (the most common mutation) have a higher risk of developing hyperhomocysteinemia after N2O anaesthesia. ;

Study Design

Endpoint Classification: Pharmacodynamics Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Basic Science

Related Conditions & MeSH terms

• Adverse Effects
• Anesthesia, General
• Nitrous Oxide

• NCT number: NCT00482456
• Study type: Interventional
• Source: Medical University of Vienna
• Status: Completed
• Phase: Phase 4
• Start date: January 2005
• Completion date: March 2007