Comparative Pharmacology
Head-to-head clinical analysis: EXTENDED PHENYTOIN SODIUM versus LYRICA CR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: EXTENDED PHENYTOIN SODIUM versus LYRICA CR.
EXTENDED PHENYTOIN SODIUM vs LYRICA CR
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Phenytoin stabilizes neuronal membranes by promoting sodium channel inactivation, reducing repetitive firing of action potentials, and decreasing synaptic transmission.
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).
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.
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
22–32 hours (mean 24 hours) in adults, dose-dependent due to saturable metabolism; may exceed 60 hours at high concentrations.
6.3 hours (mean terminal elimination half-life); correlates with creatinine clearance, prolonged in renal impairment.
Primarily hepatic metabolism (CYP2C9/CYP2C19), with <5% excreted unchanged renally. Fecal excretion accounts for minor elimination.
Primarily renal excretion as unchanged drug (98-99% of absorbed dose); <0.1% biliary/fecal.
Category D/X
Category C
Anticonvulsant
Anticonvulsant