Comparative Pharmacology
Head-to-head clinical analysis: DILANTIN versus FELBAMATE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DILANTIN versus FELBAMATE.
DILANTIN vs FELBAMATE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Phenytoin stabilizes neuronal membranes and decreases seizure activity by increasing efflux or decreasing influx of sodium ions across cell membranes in the motor cortex during generation of nerve impulses. It acts by blocking voltage-dependent sodium channels, thereby inhibiting the spread of seizure activity.
Felbamate enhances GABAergic transmission and inhibits NMDA receptor activity, likely through interaction with the glycine recognition site.
300–400 mg/day orally in 2–3 divided doses; IV loading dose 15–20 mg/kg at max 50 mg/min, then 300 mg/day IV divided 2–3 times daily.
1200-3600 mg/day orally in 3-4 divided doses; initiate at 1200 mg/day and titrate by 600-1200 mg/day every 2 weeks.
None Documented
None Documented
Clinical Note
moderateFelbamate + Estrone sulfate
"The serum concentration of Estrone sulfate can be decreased when it is combined with Felbamate."
Clinical Note
moderateFelbamate + Cyclosporine
"The metabolism of Cyclosporine can be decreased when combined with Felbamate."
Clinical Note
moderateFelbamate + Fluconazole
"The metabolism of Fluconazole can be decreased when combined with Felbamate."
Clinical Note
moderateFelbamate + Clotrimazole
Average 22 hours (range 7-42 hours) in adults. Dose-dependent; increases with higher concentrations due to saturable metabolism. In neonates: 10-15 hours. In chronic use, half-life may increase.
Terminal elimination half-life: 13-23 hours in adults (mean ~20 hours); may be prolonged to 30-40 hours in patients with hepatic impairment or those on enzyme inhibitors; clinical context: requires twice-daily dosing; steady-state reached in 4-5 days
Primarily hepatic metabolism to inactive metabolites (p-hydroxyphenyltoin and glucuronide conjugate). Less than 5% excreted unchanged in urine. Fecal excretion minimal (<2%).
Renal: approximately 90% (40-50% unchanged, remainder as metabolites including p-hydroxyfelbamate, 2-hydroxyfelbamate, and felbamate monocarbamate); fecal < 5%
Category C
Category C
Anticonvulsant
Anticonvulsant
"The metabolism of Clotrimazole can be decreased when combined with Felbamate."