Comparative Pharmacology
Head-to-head clinical analysis: DILANTIN versus TIAGABINE HYDROCHLORIDE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DILANTIN versus TIAGABINE HYDROCHLORIDE.
DILANTIN vs TIAGABINE HYDROCHLORIDE
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.
Tiagabine inhibits GABA reuptake into presynaptic neurons and glial cells by binding to the GAT-1 GABA transporter, thereby increasing synaptic GABA concentrations and enhancing inhibitory neurotransmission.
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: 4 mg orally once daily; titrate by 4-8 mg/day at weekly intervals. Maintenance: 32-56 mg/day divided 2-4 times daily. Maximum dose: 56 mg/day.
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 of 5–8 hours in healthy adults; prolonged to 12–16 hours in hepatic impairment. Reduces with enzyme-inducing co-medications.
Primarily hepatic metabolism to inactive metabolites (p-hydroxyphenyltoin and glucuronide conjugate). Less than 5% excreted unchanged in urine. Fecal excretion minimal (<2%).
Primarily hepatic metabolism via CYP3A4, with <2% excreted unchanged in urine. 63% of dose excreted in feces, 25% in urine as metabolites.
Category C
Category A/B
Anticonvulsant
Anticonvulsant