Canonical Question
NeuroPharm – LA
Master answer
Anticonvulsant Classification
(based on mechanism of action)
- Sodium channel blockers.
- Examples: phenytoin, carbamazepine, lamotrgine, Na valproate
- These promote the inactive state of voltage activated Na channels.
- Increased neuron refractory period to action potential generation.
- Rapid repetitive firing is diminished, spread of electrical activity to adjacent brain areas is suppressed.
- Drugs that enhance GABA mediated synaptic inhibition.
- Increases the influx of chloride ions into the cell and hyperpolarizes the neuron.
3 mechanisms:- Act on GABA receptor. Example: benzodiazepines, barbiturates.
- Inhibit GABA transporter and reduce neuronal GABA reuptake. Example: tiagabine.
- Promote GABA release. Example: gabapentin.
- Increases the influx of chloride ions into the cell and hyperpolarizes the neuron.
- Drugs that inhibit pre-synaptic Calcium channels.
- Example.: Na valproate, ?levetiracetam
- Limit activation of voltage activated Ca channel known as the T current
- Drugs that inhibit AMPA Kinate.
- Example.: Topiramate
- Limit proexcitatory action of glutamate
- Drugs that NT release.
- Example.: ?levetiracetam
- Binds to synaptic vesicle glycoprotein SV2A reducing exocytosis of synaptic vesicles

Exam appearances
| Exam | Exact wording | Relationship | Success |
|---|---|---|---|
| 2008A Q09 | Describe the physiological basis for the mechanism of action of three commonly used anticonvulsant groups. Give an example of a drug for each mechanism of action. | historical_member | — |
| 2023B Q04 | Classify the mechanisms of action of anti-convulsant drugs (30% marks). Outline the pharmacology of gabapentin (70% marks). | historical_member | — |