MOA

Question 1

MOA of any antiepileptic drugs on sodium channel

Answer 1

bind to voltage dependent Na+ channel( prolong the inactive state)

And prevent further entry of na+
(Stabilize neural membrane)
↓
Inhibit repetive AP
↓
Supress higher freq. Firing neuron
↓
Reduce seizure discharge

Question 2

MOA of antiepileptic on GABA, GAD, Glutamic acid decarboxylase , GABA transaminase, IPSP

Answer 2

Phenobarbitone - - ↑ GABA activity and GABA mimetic
Benzodiazepine- facilitate GABA activity

Sodium valproate- (+ )GAD.( - )GABA-T
vigabatrin. (-) GABA-T
Tiagabine. Block uptake of GABA
Gabapentin. Promote GABA release

These ↑ cl- conduction into neuron (IPSP)

hyperpolz

Reduce neuronal excitability

Antiepileptic action

Question 3

MOA of phenytoin

Answer 3

Act on na+ channel
Bind to VGna+C (↑ inactive state)
And prevent further entry

Reduce intraneuronal na+ concentration ( membrane. Stabilizing)

Decrease repetitive gen. Of ap

Question 4

MOA of carbamazepine

Answer 4

Same as phenytoin

Question 5

MOA of valproic acid

Answer 5

Like phenytoin and carbamazepine - it delay the recovery Na+ channel from inactivation

Like ethosuximide it block T type Ca++ channel in thalamic neuron

In GABA activity in brain
By ↑ syn. By stimulating GAD(glutamic acid decarboxylase)
↓ degradation of GABA by inhibiting GABA-T (gaba transaminase)