Comparative Pharmacology
Head-to-head clinical analysis: FOMEPIZOLE versus PROVAYBLUE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FOMEPIZOLE versus PROVAYBLUE.
FOMEPIZOLE vs PROVAYBLUE
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.
Methylthioninium chloride (methylene blue) acts by reducing methemoglobin to hemoglobin via the enzyme NADPH methemoglobin reductase, thereby restoring oxygen-carrying capacity of the blood.
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 mg/kg intravenously over 5 minutes, may repeat once if needed. Maximum single dose: 300 mg.
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 10-15 hours. In patients with renal impairment, half-life may be prolonged; no dose adjustment recommended for mild-to-moderate impairment, but use caution in severe impairment.
Renal: 70-90% as unchanged drug and metabolites (4-carboxypyrazole, 4-hydroxymethylpyrazole); biliary/fecal: minor (<5% total).
Primarily renal excretion as unchanged drug. Approximately 45-60% of a dose is excreted unchanged in urine. Minor fecal elimination accounts for less than 10%.
Category C
Category C
Antidote
Antidote