Comparative Pharmacology
Head-to-head clinical analysis: DILANTIN versus LYRICA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DILANTIN versus LYRICA.
DILANTIN vs LYRICA
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 α2-δ subunit of voltage-gated calcium channels, reducing calcium influx and inhibiting release of excitatory neurotransmitters including glutamate, norepinephrine, and 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.
Oral: 75-150 mg twice daily or 50-100 mg three times daily; maximum 600 mg/day. Start at 75 mg twice daily.
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 elimination half-life is 6.3 hours (range 5.5–6.7 hours) in patients with normal renal function. Half-life increases in renal impairment (up to 48 hours in anuria).
Primarily hepatic metabolism to inactive metabolites (p-hydroxyphenyltoin and glucuronide conjugate). Less than 5% excreted unchanged in urine. Fecal excretion minimal (<2%).
Renal excretion of unchanged drug accounts for approximately 90% of elimination; less than 1% is secreted in feces or bile. Dose adjustment required in renal impairment (CrCl <60 mL/min).
Category C
Category C
Anticonvulsant
Anticonvulsant