Epilepsy

EPILEPSY

Mechanism of action of antiepileptic drugs

Currently available antiepileptic drugs appear to act primarily by blocking the initiation or spread of seizures. This occurs through a variety of mechanisms, and in most cases the drugs have pleiotropic effects. The mechanisms include inhibition of Na+-dependent action potentials in a frequency-dependent manner (e.g., phenytoin, carbamazepine, topiramate, zonisamide), inhibition of voltage-gated Ca2+channels (phenytoin), decrease of glutamate release (lamotrigine), potentiation of GABA receptor function (benzodiazepines and barbiturates), and increase in the availability of GABA (valproic acid, gabapentin, tiagabine). The two most effective drugs for absence seizures, ethosuximide and valproic acid, probably act by inhibiting T-type Ca2+ channels in thalamic neurons.

In contrast to the relatively large number of antiepileptic drugs that can attenuate seizure activity, there are currently no drugs known to prevent the formation of a seizure focus following CNS injury in humans. The eventual development of such "antiepileptogenic" drugs will provide an important means of preventing the emergence of epilepsy following injuries such as head trauma, stroke, and CNS infection.

[PakMed Homepage] [Disclaimer/Privacy Policy] [Contact]

© Copyrights PakMed Biomedical Solutions

Optimized for Java-script enabled Microsoft Internet Explorer 6, at screen resolution of 800 by 600 pixels.