Comparative Pharmacology
Head-to-head clinical analysis: DILANTIN versus EPITOL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DILANTIN versus EPITOL.
DILANTIN vs EPITOL
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.
Carbamazepine stabilizes the inactivated state of voltage-gated sodium channels, thereby inhibiting high-frequency repetitive firing of action potentials and reducing synaptic transmission.
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.
Carbamazepine, immediate-release: initial 200 mg orally twice daily; increase by 200 mg/day at weekly intervals. Typical maintenance: 800-1200 mg/day in 2-3 divided doses. Extended-release: initial 200 mg orally twice daily; maintenance 400-600 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.
20-40 hours (mean 30 hours); linear kinetics at therapeutic doses; decreased with concomitant enzyme-inducing drugs
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 glucuronide conjugates and other metabolites), Fecal: 30% (unchanged and metabolites)
Category C
Category C
Anticonvulsant
Anticonvulsant