Department of Medical and Toxicological Intensive Care Medicine, Lariboisière Hospital, INSERM U1144, Paris-Diderot University, Paris, France
Methanol is responsible for a life-threatening poisoning. Fomepizole, a potent alcohol dehydrogenase inhibitor, is an efficient and safe antidote that prevents or reduces toxic methanol metabolism. Although no study has compared its efficacy with ethanol, fomepizole is recommended as a first-line antidote. Treatment should be started as soon as possible, based on history and initial findings including anion gap metabolic acidosis, while awaiting measurement of serum alcohol concentration. Administration is easy (15 mg/ kg-loading dose, either intravenously or orally, regardless of alcohol concentration, followed by intermittent 10 mg/kg-doses every 12 hours until alcohol concentration becomes less than 30 mg/dL). There is no need to monitor fomepizole concentration. If administered early, fomepizole prevents methanol-related visual and neurological injuries. When administered prior to the onset of significant acidosis or organ injury, fomepizole may obviate the need for hemodialysis. When dialysis is indicated, 1 mg/kg/h-continuous infusion should be provided to compensate for its elimination. Its side-effects are rarely serious and with a lower occurrence than ethanol. Fomepizole is contraindicated in case of allergy to pyrazoles. It is both efficacious and safe in the pediatric population, but is not recommended during pregnancy. In conclusion, fomepizole is an effective and safe first-line antidote for methanol poisoning.