Comparative Pharmacology
Head-to-head clinical analysis: CEREBYX versus DILANTIN 125.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CEREBYX versus DILANTIN 125.
CEREBYX vs DILANTIN-125
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 voltage-gated sodium channel inactivation, reducing high-frequency neuronal firing and seizure propagation.
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.
300-400 mg per day orally in divided doses (e.g., 100 mg three times daily); loading dose 1 g orally divided into three doses given at 2-hour intervals, then 100 mg every 6-8 hours for first 24 hours.
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 half-life: 7-42 hours (mean 22 hours) in adults; dose-dependent due to saturable metabolism. Steady-state reached in 7-10 days.
Renal excretion of unchanged drug and metabolites accounts for approximately 80% of the dose; about 20% is eliminated in feces via biliary excretion.
Renal: 70% as metabolites (mainly HPPA glucuronide and sulfate), 5-10% as unchanged drug. Fecal: 30% (minor).
Category C
Category C
Anticonvulsant
Anticonvulsant