Fomepizole for the treatment of methanol poisoning

Background: Methanol poisoning may result in metabolic acidosis, blindness, and death. The inhibition of alcohol dehydrogenase is fundamental to the t reatment of methanol poisoning. We performed a multicenter study to evaluat e fomepizole, an inhibitor of alcohol dehydrogenase, in the treatment of pa tients with methanol poisoning. Methods: We administered intravenous fomepizole to 11 consecutive patients who presented with methanol poisoning at a participating center. Serial cli nical and laboratory studies, including measurements of plasma formic acid and fomepizole, were performed. The outcomes measured were the preservation of visual acuity, the resolution of metabolic acidosis, the inhibition of formic acid production, the achievement of therapeutic plasma concentration s of fomepizole with the dosing regimen, residual illness or disability, an d death. Results: Plasma formic acid concentrations were detectable in eight patient s, and these concentrations were closely correlated with the initial arteri al pH values (r = 0.92, P < 0.001). In response to fomepizole, plasma formi c acid concentrations fell and metabolic abnormalities resolved in all pati ents. Nine patients survived. Seven patients initially had visual abnormali ties, but at the end of the trial no surviving patient had any detectable v isual deficits related to methanol poisoning. Fomepizole had few adverse ef fects. The two patients who died had anoxic brain injury that was present a t the time of enrollment. During treatment, methanol had an elimination hal f-life of 54 hours. Conclusions: Fomepizole appears to be safe and effective in the treatment o f methanol poisoning. (N Engl J Med 2001;344:424-9.) Copyright (C) 2001 Mas sachusetts Medical Society.