Seizure Drugs Flashcards
seizures are due to increased or decreased circuit output in brain’?
increased
describe the character of the brain firing in seizures
disordered and synchronous
status epilepticus is what?
seizure longer than 5 mins or two within 5 mins
what are two types of seizures?
partial or generalized
what are two types of partial seizures?
simple and complex
do you lose consciousness in simple partial seizure?
no
do you lose consciousness in complex partial seizure?
yes
do you lose consciousness in generalized seizures?
yes..in all types
name the four ion changes that can lead to seizures
decreased Cl influx
decreased K+ efflux
increased Na or Ca influx
name the four seizure meds that are inhibitors of the voltage gated Na channels
carbamazepine
lamotrigine
phenytoin
valproate
how do Na channel blockers actual block the NA channels?
slow transition from inactivated to resting state…increase refractory period
what is common toxicity with phenytoin?
gingival hyperplasia
what is toxicity with carbamazepine?
water retention and hyponatremia
how does carbamazepine induce water retention and hyponatremia?
increased ADH
what are the two toxicities of valproate?
alopecia and weight gain
what is MoA of valproate?
voltage Na blocker
what is MoA of carbamazepine?
voltage Na blocker
what is MoA of phenytoin?
voltage Na blocker
what is MoA of lamotrigine?
voltage Na blocker
aside from voltage gated Na channel blockers what is another presynaptic mechanism to block excitatory pathway in seizures?
voltage gated caclium channel blockers
name the two voltage gated calcium channel blockers for seizures
gabapentin and pregabalin
what Nt tract do gabapentin and pregabalin work in?
glutamate
what is MoA of gabapentin?
block Vg Ca channels in glutamate path
what is MoA of pregabalin?
block Vg Ca channels in glutamate path
what is the molecular target of levetiracetam?
SV2A
what is SV2A important for?
vesicle fusion for Nt release of glutamate
what drug targets the SV2A vesicle fusion protein?
levetiracetam
what does levetiracetam prevent?
vesicle fusion and Nt release of glutamate
how do topiramate and felbamate work to be anti seizure?
block ligand gated Na channels in post synaptic neuron in glutamate tracts
name the two drugs that block glutamate post synaptic ligand gated Na channels
topiramate and felbamate
what is the target of topiramate?
AMPA
what is the target of felbamate?
NMDA
what are two severe tox of felbamate?
aplastic anemia and acute liver failure
what are two tox of topiramate?
weight loss and renal calculi
what is MoA of ethosuximide?
slows Ca2+ induced depol in post synaptic neuron in Glutamate tract
what is drug that inhibits Ca2+ entry into post synaptic neuron in glutamate tract?
ethosiximide
what is MoA of tiagabine?
reuptake inhib of GABA
what Nt path does tiagabine work in?
GABA
what drug inhibits uptake of GABA?
tiagabine
what is MoA of vigabatrin and valproate in GABA pathway?
they inhibit breakdown of GABA in pre synaptic neuron
what two drugs inhibit breakdown of GABA in pre synaptic neuron?
vigabatrin and valproate
what is side effect of vigabatrin?
progressive permanent blindnes
what is class of drugs that positively modulates GABA receptors on post synaptic neurons and is used to treat seizures?
Benzos
what is main benzo ued for anti seizure med?
clonazepam
aside from benzos what other class of meds can positively modulate GABA receptor in seizure treatment?
phenobarbitol
what drug for anti seizure inhibits CYP2C9?
valproate
inhibiting CYP2C9 leads to increase in conc of what drugs?
lot of other anti seizures…carbamazepine, phenytoin, topiramate, felbamate, lamotrigine
what two anti seizure drugs induce CYP3A4
phenytoin and carbamazepine
how is phenytoin cleared at high dose?
zero order…saturated…constant mg/hour, T1/2 not constant
how is phenytoin cleared at low conc?
1st order, T1/2 constant
what two seizure drugs lead to ineffective OCP use?
phenytoin and carbamazepine
how do phenytoin and carbamazepine lead to ineffective OCP?
induce CYP3A4 which leads to quick breakdown of ethinyl estradiol making OCP ineffective
name the four seizure meds that are teratogenic
phenytoin
carbamazepine
topiramate
valproate
name the two seizure drugs that decreae folate in women of child bearinf age
carbamazepine and phenytoin
