Comparative Pharmacology
Head-to-head clinical analysis: FOMEPIZOLE versus SODIUM NITRITE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FOMEPIZOLE versus SODIUM NITRITE.
FOMEPIZOLE vs SODIUM NITRITE
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.
Sodium nitrite is a vasodilator that acts by relaxing vascular smooth muscle, primarily through the generation of nitric oxide (NO). It also converts hemoglobin to methemoglobin, which binds cyanide, thereby acting as an antidote for cyanide poisoning.
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.
300 mg (10 mL of a 30 mg/mL solution) intravenously over 2-4 minutes, followed immediately by sodium thiosulfate. May repeat once after 30-60 minutes if needed.
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 half-life: 0.5–1 hour (nitrite); due to rapid oxidation to nitrate, which has a half-life of 5–8 hours. Clinically, methemoglobin reduction requires monitoring for 2–4 hours.
Renal: 70-90% as unchanged drug and metabolites (4-carboxypyrazole, 4-hydroxymethylpyrazole); biliary/fecal: minor (<5% total).
Primarily renal; 60-70% as nitrate and unchanged nitrite; minor biliary (<5%) and fecal (<2%) elimination.
Category C
Category C
Antidote
Antidote