Phenytoin
DilantinPubChem CID 1775 · 3D model
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Jams a nerve cell's sodium-channel 'reset switch' in the off position a little longer, calming the rapid-fire signaling of a seizure without shutting down normal nerve activity.
How it works
Phenytoin works by jamming a switch that nerve cells use to fire electrical signals — specifically, a channel that lets sodium into the cell. It locks onto the channel's 'just fired' state and holds it there longer, so overactive nerve cells firing rapidly and repeatedly, the pattern seen during a seizure, get slowed down much more than nerve cells firing normally. That's the same basic type of channel-blocking trick lidocaine uses, also on this site, but the two drugs work in very different places: lidocaine numbs one small area right where it's applied, while phenytoin travels through the bloodstream to calm overactive firing throughout the brain. It's also a completely different mechanism from gabapentin, also on this site, which targets a calcium channel, not a sodium channel.
What it’s used for
Used to control the two major types of epileptic seizures, generalized convulsive seizures and complex partial seizures arising in the temporal lobe, and to prevent or treat seizures that can occur during or after brain surgery.
- Mechanism
- Voltage-gated sodium channel blocker (preferential inactivated-state binding)
- Drug class
- Small molecule
- Therapeutic area
- CNS / Neurology