Comparative Pharmacology
Head-to-head clinical analysis: DEPAKOTE CP versus PHENYTOIN SODIUM.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DEPAKOTE CP versus PHENYTOIN SODIUM.
DEPAKOTE CP vs PHENYTOIN SODIUM
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Valproate increases GABA concentration in the brain by inhibiting GABA transaminase and succinic semialdehyde dehydrogenase. It also blocks voltage-gated sodium channels and T-type calcium channels.
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. Prolongs inactivation of voltage-gated sodium channels, reducing repetitive firing of action potentials.
250-500 mg orally twice daily, titrated by 250 mg/day every 3-7 days; maximum 60 mg/kg/day. Target trough serum concentration: 50-100 mcg/mL.
Loading dose: 15-20 mg/kg IV (not to exceed 50 mg/min) or oral (1000-1500 mg total in divided doses). Maintenance: 300-400 mg/day PO in 1-2 divided doses or IV (100 mg every 6-8 hours).
None Documented
None Documented
Terminal elimination half-life is 9-16 hours (mean ~12 hours) in adults; prolonged in hepatic impairment, elderly, and neonates.
Mean terminal half-life 22 ± 9 hours (range 7–42 hours), dose-dependent and saturable due to Michaelis-Menten kinetics; half-life increases with higher serum concentrations. Steady state achieved after 7–10 days.
Renal: 30-50% as glucuronide conjugates, 3% as unchanged drug; fecal: minimal; less than 3% excreted in bile.
Primarily hepatic metabolism (CYP2C9, CYP2C19); <5% excreted unchanged in urine. Metabolites (majority p-HPPA) are excreted renally as glucuronide conjugates. Fecal elimination negligible (<2%).
Category C
Category D/X
Anticonvulsant
Anticonvulsant