Sodium channel blockers in epilepsia

Another field of application for sodium channel blockers is epilepsia. While epileptic seizures are a diverse and com-plex phenomenon, a key feature consists in bursts of excess excitatory activity of neurons in the brain. Sodium chan-nel blockers will reduce nerve cell excitability, and they are thus one of the mainstays of anti-epileptic treatment. As but one example out of many7, Figure 5.10 shows pheny-toin (or diphenylhydantoine).

Properties of phenytoin are

• good penetration of blood brain barrier;

• action on several cation channels besides Na V. The contribution of these to the therapeutic effect is unsettled;

• strong enzyme induction (hepatic metabolism, CYP3A3). This gives rise to multiple drug interactions.

These characteristics are quite common among antiepilep-tic drugs.