pharm of epilepsy

what is the name of drugs that inhibit voltage gated Na+ channels

lamotrigine, valproate, carbamazepine, phenytoin

what does carbamazepine, phenytoin, lamotrigine and valproate do

usage dependent blocking of voltage gated Na+ channels

• preferential binding of inactive Na channels

• this state is more common in high frequency firing neurons

• blocks high firing frequency neurons and leaves normal neurons alone

what is the name of a drug that blocks T type Ca2+ channels

ethosuximide

what does ethosuximide do

blocks voltage gated L-type Ca2+ channels which are crucial in burst pattern firing that causes spike wave complexes

what is the name of a drug that stimulates M type voltage gated K+ channels

retigabine

what does retigabine do

stimulates M-type voltage gated K+ channels by binding to KCNQ2 and 5 which causes repolarisation of neurons

name of drugs inhibiting GABA metabolism

valproate, vigabatrin

what does valproate and vigabatrin do

they inhibit GABA transaminase

increased [GABA] causes transporters to work in reverse releasing GABA into the synapse

name of drugs that modulate GABA activity

• benzodiazepines: diazepam, lorazepam, clonazepam

  • barbiturates: phenobarbitone

how do BDZ and barbiturates work

bind to allosteric sites on the pentameric GABA-A receptor shifting dose response curve to the left (positive allosteric modulators)

name of drugs inhibiting GABA uptake

tiagabine

what does tiagabine do

inhibits GAT-1 uptake transporters of GABA

name of drug acting on NMDA

Felbamate

what does felbamate do

binds to glycine site of NMDA receptors inhibitng post-synaptic excitation

side effects of felbamate

• aplastic anaemia

  • hepatotoxicity

name of drug that inhibits AMPA

Perampanel

what does perampanel do

non-competitive inhibitor of AMPA receptors

name of drug that inhibits glutamate release by binding to SV2A

levetiracetam

what does levetiracetam do

it block SV2A receptors on vesicle preventing glutamate release

how can a ketogenic diet help with epilepsy

• increases fatty acid oxidation producing ketones

  • there is a medium chain FA called decanoic acid that acts as a non-competitive AMPA channel inhibitor

what are the side effect of anti-epileptic drugs

• drugs are teratogenic

• phenytoin, valproate and carbamazepine are inducers of CP450

• phenytoin is eliminated by 0 order kinetics