Comparative Pharmacology
Head-to-head clinical analysis: ANTIZOL versus FUSILEV.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ANTIZOL versus FUSILEV.
ANTIZOL vs FUSILEV
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Antizol (fomepizole) is a competitive inhibitor of alcohol dehydrogenase, the enzyme that catalyzes the oxidation of ethanol to acetaldehyde. It also inhibits the metabolism of ethylene glycol and methanol to their toxic metabolites.
FUSILEV (levoleucovorin) is the pharmacologically active isomer of folinic acid. It bypasses dihydrofolate reductase inhibition by dihydrofolate reductase inhibitors (e.g., methotrexate), providing reduced folate that is used in DNA synthesis and repair. It also enhances the efficacy of fluorouracil by stabilizing the ternary complex of thymidylate synthase, thereby inhibiting DNA synthesis.
Initial: 15 mg/kg IV over 10 minutes, then 3 mg/kg IV every 4 hours for 2 doses, then 3 mg/kg IV every 6 hours for 4 doses.
Leucovorin (Fusilev) 200 mg/m2 IV over 2 hours, followed by 5-fluorouracil bolus and infusion, repeated every 2 weeks in combination regimens for advanced colorectal cancer.
None Documented
None Documented
Terminal elimination half-life: 2.5-3.5 hours in adults. Clinical context: Dose adjustment recommended in severe renal impairment (CrCl <30 mL/min) due to prolonged half-life.
The terminal elimination half-life of the active metabolite, 5-methyltetrahydrofolate (5-MTHF), is approximately 6-8 hours in healthy adults; clinically, this supports twice-daily or daily dosing schedules.
Renal: 80-95% as parent drug and metabolites. Fecal: <5%. Biliary excretion is negligible.
Primarily hepatic metabolism; renal excretion of metabolites accounts for approximately 40-60% of the dose; fecal excretion is negligible.
Category C
Category C
Antidote
Antidote