Comparative Pharmacology
Head-to-head clinical analysis: DILANTIN versus LYRICA CR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DILANTIN versus LYRICA CR.
DILANTIN vs LYRICA CR
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.
Binds to the alpha-2-delta subunit of voltage-gated calcium channels in the central nervous system, reducing calcium influx and inhibiting excitatory neurotransmitter release (e.g., glutamate, norepinephrine, substance P).
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.
Initial 75 mg orally twice daily (150 mg/day), or 50 mg three times daily (150 mg/day). Based on efficacy and tolerability, may increase to 150 mg twice daily (300 mg/day) after 1 week, then to 225 mg twice daily (450 mg/day) if needed. Maximum dose 450 mg/day. Take with food. Administer whole; do not split, crush, or chew.
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.
6.3 hours (mean terminal elimination half-life); correlates with creatinine clearance, prolonged in renal impairment.
Primarily hepatic metabolism to inactive metabolites (p-hydroxyphenyltoin and glucuronide conjugate). Less than 5% excreted unchanged in urine. Fecal excretion minimal (<2%).
Primarily renal excretion as unchanged drug (98-99% of absorbed dose); <0.1% biliary/fecal.
Category C
Category C
Anticonvulsant
Anticonvulsant