Comparative Pharmacology
Head-to-head clinical analysis: PHENYTOIN versus VIGPODER.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PHENYTOIN versus VIGPODER.
PHENYTOIN vs VIGPODER
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Phenytoin is a hydantoin anticonvulsant that 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 use-dependently blocks voltage-gated sodium channels, prolonging their inactivation phase and reducing high-frequency repetitive firing of action potentials.
VIGPODER (vigabatrin) is an irreversible inhibitor of GABA transaminase, leading to increased brain levels of gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter.
Oral: 300-400 mg/day in 3-4 divided doses; IV: 15-20 mg/kg loading dose, then 300 mg/day maintenance.
150 mg orally twice daily with or without food.
None Documented
None Documented
Clinical Note
moderatePhenytoin + Digoxin
"The metabolism of Digoxin can be increased when combined with Phenytoin."
Clinical Note
moderateFosphenytoin + Digoxin
"The metabolism of Digoxin can be increased when combined with Fosphenytoin."
Clinical Note
moderatePhenytoin + Digitoxin
"The metabolism of Digitoxin can be increased when combined with Phenytoin."
Clinical Note
moderateFosphenytoin + Digitoxin
"The metabolism of Digitoxin can be increased when combined with Fosphenytoin."
Average terminal half-life 22 hours (range 7–42 hours) in adults; dose-dependent due to saturation of metabolism at therapeutic concentrations (10–20 mg/L). Half-life increases with higher doses.
12 hours (range 10–14 hours) in healthy adults; prolonged to 24–30 hours in moderate renal impairment (CrCl 30–50 mL/min).
Primarily hepatic metabolism (>95%); less than 5% excreted unchanged in urine. Renal excretion of metabolites (glucuronides) accounts for ~80% of elimination; biliary/fecal excretion of metabolites ~20%.
Renal: 70% as unchanged drug; biliary/fecal: 20% as metabolites; 10% via other routes.
Category D/X
Category C
Anticonvulsant
Anticonvulsant