Phenytoin, Carbamazepine | Block voltage-dependent sodium channels at high firing frequencies |
Barbiturates |
Prolong GABA-mediated chloride channel openings Some blockade of voltage-dependent sodium channels |
Benzodiazepines | Increase frequency of GABA-mediated chloride channel openings |
Felbamate |
May block voltage-dependent sodium channels at high firing frequencies May modulate NMDA receptor via strychnine-insensitive glycine receptor |
Gabapentin |
Increases neuronal GABA concentration Enhances GABA mediated inhibition |
Topiramate • Blocks voltage-dependent sodium channels at high firing frequencies • Increases frequency at which GABA opens Cl- channels (different site than benzodiazepines) • Antagonizes glutamate action at AMPA/kainate receptor subtype • Inhibition of carbonic anydrase |
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Lamotrigine |
Blocks voltage-dependent sodium channels at high firing frequencies May interfere with pathologic glutamate release |
Ethosuximide | Blocks low threshold, “transient” (T-type) calcium channels in thalamic neurons |
Valproate |
May enhance GABA transmission in specific circuits Blocks voltage-dependent sodium channels |
Vigabatrin | Irreversibly inhibits GABA-transaminase |
Tiagabine | Interferes with GABA re-uptake |
Levetiracetam |
Binding of reversible saturable specific binding site Reduces high-voltsge- activated Ca2+ currents Reverses inhibition of GABA and glycine gated currents induced by negative allosteric modulators |
Oxcarbazepine |
Blocks voltage-dependent sodium channels at high firing frequencies Exerts effect on K+ channels |
Zonisamide |
Blocks voltage-dependent sodium channels and T-type calcium channels |