Fomepizole versus ethanol in the treatment of acute methanol poisoning: Comparison of clinical effectiveness in a mass poisoning outbreak
Abstract
Context. Mass or cluster methanol poisonings are frequently reported from around the world.
The comparative effectiveness of ethanol and fomepizole as antidotes for methanol poisoning is unknown due to the difficulty of performing a randomized controlled trial. Objective.
During an outbreak of mass poisonings in the Czech Republic in 2012-2014, we compared the effects of antidotes on the frequency of health sequelae and mortality. Methods.
The study was designed as a cross-sectional case series and quasi-case-control study. Patients with a diagnosis of methanol poisoning on admission to hospitals were identified for the study.
Diagnosis was established when (i) a history of recent ingestion of illicit spirits was available and serum methanol was higher than 6.2 mmol/L (20 mg/dL), or (ii) there was a history/clinical suspicion of methanol poisoning, and serum methanol was above the limit of detection with at least two of the following: pH 20 mmol/L. Fomepizole was given as a bolus dose of 15 mg/kg i.v. diluted in isotonic saline, followed by 10 mg/kg every 12 h (every 4 h during hemodialysis); ethanol was administered both intravenously as a 10% solution in 5% glucose, and per os in boluses of 20% solution.
Multivariate regression was applied to determine the effect of antidote on outcome. Additionally, for a retrospective quasi-case-control study, a control group of patients treated with ethanol, matched carefully on severity of poisoning and other key parameters, was selected.
Conclusions. This study on antidotes for methanol poisoning did not show any evidence of different clinical effectiveness.
Although ethanol is generally associated with a higher incidence of complications, this study suggests that both antidotes are similarly effective and that ethanol should not be avoided on grounds of effectiveness.