Comparative Pharmacology
Head-to-head clinical analysis: FOMEPIZOLE versus PRALIDOXIME CHLORIDE AUTOINJECTOR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FOMEPIZOLE versus PRALIDOXIME CHLORIDE AUTOINJECTOR.
FOMEPIZOLE vs PRALIDOXIME CHLORIDE (AUTOINJECTOR)
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.
Reactivates acetylcholinesterase inhibited by organophosphate poisoning by binding to the organophosphate moiety.
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 or IM, repeat after 1 hour if muscle fasciculations persist, then every 6-12 hours as needed. Administer as a 5% solution (1g in 20mL) over 5-10 minutes IV; IM into deltoid or anterolateral thigh.
None Documented
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."
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 1.2-2.5 hours in adults with normal renal function. In organophosphate poisoning, prolonged half-life may occur due to redistribution or renal impairment; clinical context: requires repeated dosing or continuous infusion to maintain therapeutic concentrations.
Renal: 70-90% as unchanged drug and metabolites (4-carboxypyrazole, 4-hydroxymethylpyrazole); biliary/fecal: minor (<5% total).
Primarily renal excretion of unchanged drug and metabolites; approximately 80-90% of a dose is excreted in urine within 4-6 hours, with 50% as unchanged pralidoxime and the remainder as metabolites (e.g., 1-methyl-2-pyridone-2-aldoxime). Minor biliary/fecal elimination (<10%).
Category C
Category C
Antidote
Antidote