Comparative Pharmacology
Head-to-head clinical analysis: DEPAKOTE CP versus DILANTIN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DEPAKOTE CP versus DILANTIN.
DEPAKOTE CP vs DILANTIN
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.
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.
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.
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.
None Documented
None Documented
Terminal elimination half-life is 9-16 hours (mean ~12 hours) in adults; prolonged in hepatic impairment, elderly, and neonates.
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.
Renal: 30-50% as glucuronide conjugates, 3% as unchanged drug; fecal: minimal; less than 3% excreted in bile.
Primarily hepatic metabolism to inactive metabolites (p-hydroxyphenyltoin and glucuronide conjugate). Less than 5% excreted unchanged in urine. Fecal excretion minimal (<2%).
Category C
Category C
Anticonvulsant
Anticonvulsant