Anticonvulsants: part 3 Flashcards
What drug inhibits SV2A
Levetiracetam
What is the mechanism of levetiracetam
Binds to synaptic vesicle associated protein (SV2A) preventing glutamate release
PK of levetiracetam
Fast onset, half life 10hrs
Infications of levetiracetam
Myoclonic
What drugs block postsynaptic membane receptors
Topiramate
What is the mechanism of topiramate action
Inhibits NMDA & kainate receptors Also affects VGSCs & GABA receptors
What is the PK of topiramate
Fast-onset (1 hour); long half-life (20 hours)
Indication of topiramate
Myoclonic seizures and neuropathic pain (more)
Action at GABA receptor
DIFFERENCE TO OTHERS: there is always a small amount of GABA released as the brain is always in an inhibitory mode GABA can be released tonically & also following neuronal stimulation
How does GABA get released and work on receptor
GABA activates inhibitory post-synaptic GABAA receptors GABAA receptors are chloride (Cl-) channels–> membrane hyperpolarisation GABA is taken up by GAT & metabolised by GABA transaminase (GABA-T)
What is the acton of diazepam
GABA receptor, PAM –> increases GABA-mediated inhibition POSITIVE ALLOSTERIC MODULATOR I.e. BDZs cannot activate the GABA-A receptor without the normal GABA ligand bindin
What is the indication of diazepam in epilepsy + how it is administered in this case
Rectal gel - Fast-onset (within 15 min); half-life (2 hours) for Status epilepticus
Function of sodium valproate
Inhibits GABA transaminase –> increases GABA-mediated inhibition
What does GABA transaminase do
Converts GABA-A to glutamate So with sodium valproate, a GAT inhibitor, you will have less Glu and more GABA :)
What is the infication for sodium valproate
Indicated for ALL forms of epilepsy
