Comparative Pharmacology
Head-to-head clinical analysis: FUSILEV versus PROTOPAM CHLORIDE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: FUSILEV versus PROTOPAM CHLORIDE.
FUSILEV vs PROTOPAM CHLORIDE
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.
Reactivates acetylcholinesterase inhibited by organophosphate poisoning by binding to the organophosphate moiety, forming a complex that undergoes hydrolysis to regenerate active enzyme. Also has a direct neutralization effect on certain organophosphates.
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.
1-2 g IV over 15-30 minutes, may repeat after 1 hour if muscle weakness persists, then every 3-8 hours as needed for 24-48 hours.
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 elimination half-life is approximately 1.7 hours in adults. In renal impairment, half-life may be prolonged up to 6 hours, requiring dose adjustment.
Primarily hepatic metabolism; renal excretion of metabolites accounts for approximately 40-60% of the dose; fecal excretion is negligible.
Renal excretion is the primary route, with 80-90% of a dose eliminated unchanged in urine within 30 minutes; the remainder is metabolized and excreted fecally.
Category C
Category C
Antidote
Antidote