Comparative Pharmacology
Head-to-head clinical analysis: CEREBYX versus DEPAKOTE CP.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CEREBYX versus DEPAKOTE CP.
CEREBYX vs DEPAKOTE CP
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Fosphenytoin is a prodrug of phenytoin, which stabilizes neuronal membranes by blocking voltage-gated sodium channels, thereby inhibiting repetitive firing of action potentials.
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.
Loading dose: 15-20 mg PE/kg IV/IM (max 1500 mg PE); maintenance: 4-6 mg PE/kg/day IV/IM divided q12h or q8h. Switch to oral phenytoin at equivalent dose.
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.
None Documented
None Documented
The terminal elimination half-life of fosphenytoin (converted to phenytoin) is approximately 15 hours (range 10-20 hours) in adults with normal hepatic function; after conversion, phenytoin half-life is dose-dependent and averages 22 hours (range 7-42 hours) at therapeutic concentrations.
Terminal elimination half-life is 9-16 hours (mean ~12 hours) in adults; prolonged in hepatic impairment, elderly, and neonates.
Renal excretion of unchanged drug and metabolites accounts for approximately 80% of the dose; about 20% is eliminated in feces via biliary excretion.
Renal: 30-50% as glucuronide conjugates, 3% as unchanged drug; fecal: minimal; less than 3% excreted in bile.
Category C
Category C
Anticonvulsant
Anticonvulsant