Comparative Pharmacology
Head-to-head clinical analysis: CEREBYX versus EXTENDED PHENYTOIN SODIUM.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CEREBYX versus EXTENDED PHENYTOIN SODIUM.
CEREBYX vs EXTENDED PHENYTOIN SODIUM
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.
Phenytoin stabilizes neuronal membranes by promoting sodium channel inactivation, reducing repetitive firing of action potentials, and decreasing synaptic transmission.
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.
Oral: 100 mg three times daily; intravenous: 10-20 mg/kg loading dose at a maximum rate of 50 mg/min, then 100 mg every 6-8 hours maintenance.
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.
22–32 hours (mean 24 hours) in adults, dose-dependent due to saturable metabolism; may exceed 60 hours at high concentrations.
Renal excretion of unchanged drug and metabolites accounts for approximately 80% of the dose; about 20% is eliminated in feces via biliary excretion.
Primarily hepatic metabolism (CYP2C9/CYP2C19), with <5% excreted unchanged renally. Fecal excretion accounts for minor elimination.
Category C
Category D/X
Anticonvulsant
Anticonvulsant