(FDA Category 1S)
Fomepizole is an alcohol dehydrogenase inhibitor.
Dosing Information: For ethylene glycol intoxication, intravenous fomepizole should be administered as a loading dose of 15 mg/kg followed by 10 mg/kg every 12 hours for 4 doses, then 15 mg/kg every 12 hours thereafter until ethylene glycol levels are below 20 mg/dL. All doses should be administered via slow intravenous infusion over 30 minutes. During hemodialysis, the frequency of dosing is increased to every 4 hours.
Pharmacokinetics: Therapeutic serum levels in ethylene glycol poisoning are 100 to 300 mcmol/L (8 to 24.6 mg/L). Protein binding is minimal; volume of distribution is between 0.6 and 1.02 L/kg. Urinary excretion of unchanged compound is 1% to 4%, indicating that metabolism is the primary route of clearance. Fomepizole is metabolized in the liver. Hemodialysis removes significant amounts of the drug.
Clinical Applications: Fomepizole has shown efficacy as an ethanol alternative for the early or late treatment of ethylene glycol intoxication. Clinical data regarding its use in methanol poisoning are emerging.
Updated: August 26, 1998