Comparative Pharmacology
Head-to-head clinical analysis: DILANTIN versus FELBATOL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DILANTIN versus FELBATOL.
DILANTIN vs FELBATOL
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 is a GABA receptor agonist and modulates NMDA receptor activity, though its exact mechanism is not fully understood. It appears to enhance GABA-mediated inhibition and inhibit voltage-gated sodium channels, reducing neuronal excitability.
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; initial titration recommended.
None Documented
None Documented
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.
20-23 hours; steady state reached within 3-5 days; may be prolonged in hepatic impairment.
Primarily hepatic metabolism to inactive metabolites (p-hydroxyphenyltoin and glucuronide conjugate). Less than 5% excreted unchanged in urine. Fecal excretion minimal (<2%).
Renal: 40-50% unchanged; Hepatic metabolism accounts for ~50% with glucuronidation and oxidation; minimal biliary/fecal excretion (<5%).
Category C
Category C
Anticonvulsant
Anticonvulsant