1B4 - AED MOA

Question 1

What is the mechanism of action of levetiracetam?

Answer 1

Selectively binds to the presynpatic vessicle protein SV2A

Question 2

What is the mechanism of action of Phenobarbital?

Answer 2

1) Prolongs opening of Cl- channels on post-synaptic membranes
2) Decreases intraneuronal Na, inhibits Ca influx, raises brain serotonin levels
3) Inhibits noradrenalin reuptake by synaptosomes
4) Exhibits GABA-like effects

Question 3

What is the mechanism of action of bromides (potassium, sodium)?

Answer 3

Competes with Cl- transport across cell membrans, causing hyperpolalization

Question 4

What is the mechanism of action of topiramate?

Answer 4

Increases GABA binding to GABA receptors

1) Blocks repetitive action potentials from sustained depolarization of neurons
2) Increases the frequency that GABA activates GABA receptors
3) Antagonizes kainite/ AMPA receptors without affecting the NMDA subtype

Question 5

What is the mechanism of action of zonisamide?

Answer 5

1) Reduces infward flow at Na and T-type Ca channels
2) Has carbonic anhydrase inhibitory activity and can scavenge free radicals within the brain

Question 6

What is the mechanism of action of imepitoin?

Answer 6

1) Low affinity partial agonist at benzo binding sites of GABA receptors
2) Weak inhibition of neuronal calcium channels

Question 7

What is the mechanism of action of felbamate?

Answer 7

Unknown mechanism of action

May increase activation of Na channels to decrease sustained high frequency firing

Question 8

What is the mechanism of action of benzodiazepines?

Answer 8

1) Bind to GABA receptors and increase their affinity to GABA
2) May increase the release of GABA and decrease turnover of acetylcholine in the CNS
3) Some (clorazepate) also antagonize serotonin

Question 9

What is the mechanism of action of phenytoin?

Answer 9

1) Promotes Na efflux from neurons thereby inhibiting the spread of seizure activity in the motor cortex