Comparative Pharmacology
Head-to-head clinical analysis: FUSILEV versus SODIUM NITRITE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FUSILEV versus SODIUM NITRITE.
FUSILEV vs SODIUM NITRITE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
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.
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.
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
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.
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.
Primarily hepatic metabolism; renal excretion of metabolites accounts for approximately 40-60% of the dose; fecal excretion is negligible.
Primarily renal; 60-70% as nitrate and unchanged nitrite; minor biliary (<5%) and fecal (<2%) elimination.
Category C
Category C
Antidote
Antidote