Comparative Pharmacology
Head-to-head clinical analysis: FOMEPIZOLE versus PRALIDOXIME CHLORIDE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FOMEPIZOLE versus PRALIDOXIME CHLORIDE.
FOMEPIZOLE vs PRALIDOXIME CHLORIDE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Fomepizole is a competitive inhibitor of alcohol dehydrogenase, the enzyme that catalyzes the first step in the metabolism of ethylene glycol and methanol to their toxic metabolites. By inhibiting alcohol dehydrogenase, fomepizole prevents the formation of toxic metabolites such as glycolic acid, glyoxylic acid, and oxalic acid from ethylene glycol, and formic acid from methanol.
Pralidoxime chloride is a cholinesterase reactivator. It reactivates acetylcholinesterase that has been inactivated by phosphorylation due to organophosphate or carbamate exposure by binding to the organophosphate moiety and cleaving the enzyme-phosphate bond, thereby restoring enzymatic activity. It also has direct antimuscarinic and antinicotinic effects at high doses.
Loading dose of 15 mg/kg intravenously over 15 minutes, followed by 10 mg/kg every 12 hours for 4 doses, then 15 mg/kg every 12 hours if ethanol co-ingestion is present; otherwise 10 mg/kg every 12 hours until ethylene glycol or methanol levels <20 mg/dL.
1-2 g IV over 15-30 minutes, may repeat in 1 hour if muscle weakness persists, then every 10-12 hours as needed; typically given with atropine. Maximum dose: 2 g/hour or 12 g/day.
None Documented
Clinical Note
moderateFomepizole + Artesunate
"The serum concentration of the active metabolites of Artesunate can be reduced when Artesunate is used in combination with Fomepizole resulting in a loss in efficacy."
None Documented
Terminal: 5-7 hours in healthy adults; prolonged to 8-14 hours in patients with ethanol co-ingestion due to competitive inhibition; no significant change in severe renal impairment.
Terminal elimination half-life is approximately 1.5–2.5 hours in adults. In renal impairment, half-life may be prolonged up to 5–6 hours, necessitating dose adjustment.
Renal: 70-90% as unchanged drug and metabolites (4-carboxypyrazole, 4-hydroxymethylpyrazole); biliary/fecal: minor (<5% total).
Renal: >90% as unchanged drug and metabolites (including pyridone and pyridinium derivatives). Biliary/fecal: <5%.
Category C
Category C
Antidote
Antidote