Comparative Pharmacology
Head-to-head clinical analysis: DILANTIN versus DILANTIN 125.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DILANTIN versus DILANTIN 125.
DILANTIN vs DILANTIN-125
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
Phenytoin stabilizes neuronal membranes by promoting voltage-gated sodium channel inactivation, reducing high-frequency neuronal firing and seizure propagation.
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.
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
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.
Terminal half-life: 7-42 hours (mean 22 hours) in adults; dose-dependent due to saturable metabolism. Steady-state reached in 7-10 days.
Primarily hepatic metabolism to inactive metabolites (p-hydroxyphenyltoin and glucuronide conjugate). Less than 5% excreted unchanged in urine. Fecal excretion minimal (<2%).
Renal: 70% as metabolites (mainly HPPA glucuronide and sulfate), 5-10% as unchanged drug. Fecal: 30% (minor).
Category C
Category C
Anticonvulsant
Anticonvulsant