Anticonvulsant Drugs - Kinder Flashcards
epilepsy
2 unprovoked seizures - separated 24 hours
path of epilepsy
hyperexcitable and hypersynchronous neurons
partial seizures
focal - localized onset
simple partial seizure
patient retains awareness
complex partial seizure
patient lose consciousness
secondary generalized seizure
from partial - to both hemispheres
generalized seizure
both brain hemispheres
tonic clonic seizure
generalized - grand mal
absence seizure
generalized - blank stare
young children and adolescents
myoclonic jerking
brief shock-like movement - wide variety of seizurs
atonic seizures
loss of postural control - slumping
anti-epileptic drugs
suppress seizures
-do not cure or prevent epilepsy
tx of epilepsy
monotherapy preferred
increase dose gradually
monitor treatment regularly
compliance essential - warn patient not to stop taking med
AED MOAs
1 affect ion channel kinetic - delay Na channel recovery
2 augment inhibitor neurotransmission - GABA increase
3 modulate excitatory neurotransmission - decreased glutamate
AEDs protein bound
all - except
phenytoin
tigabine
valproic acid
adverse of AEDs
neurotoxic - sedation, dizzy, double vission
phenytoin MOA
bind and prolong inactivated state of Na channel
also decreased glutamate and increased GABA
phenytoin PK
don’t give IM - may precipitate
can give fosphenytoin (prodrug) IV or IM
phenytoin DDI
inhibits affects of warfarin
phenytoin ADR
diplopia, ataxia, nystagmus, sedation
gingival hyperplasia**
osteomalacia
hypotension, bradycardia, arrhythmia - so give slowly
gingival hyperplasia
ADR of phenytoin
carbamazepine MOA
prolong inactivation state of Na channels
inhibit high frequency firing rate
autoinduction
with carbamazepine
induces own metabolism
half life decreases over time - so levels fall
need to increase dose
asian patient with HLA V1502 allele
10x higher steven johnson syndrome with carbamazepine
gabapentin MOA
analog of GABA
-modify synaptic and non-synaptic release of GABA
bind alpha2delta subunit of voltage Na channels - decrease Ca entry - and decrease glutamate release
gabapentin ADR
HA and tremor
lamotrigine MOA
prolong inactivation state of Na channel
suppress rapid firing
lamotrigine ADR
skin rash, HA, dizzy, ataxia
lamotrigine DDI
concentration decrease with use of OCP
can also lead to contraceptive faliure
levetiracetam MOA
bind synaptic vesicle protein SV2A
-modified release of glutamate and GABA
levetiracetam ADR
serious mood and behavior change
topiramate MOA
block voltage Na channels, increase Cl opening by binding GABA receptors, reduce Ca currents
tipiramate ADR
paresthesia, weight loss
migrain tx
topiramate
ethosuximide MOA
reduce Ca threshold - T type current
-this current provide pacemaker current in thalamus for absence attacks
lennes-gestaut syndrome
childhood onset epilepsy
-frequent seizures of different types
ethosuximide ADR
gastric distress - so can’t do 1x/day
valproic acid MOA
prolong Na channel inactiviation
block NMDA
increased GABA
high level valproic acid
see tremor
valproic acid ADR
hepatotoxicity
need to monitor liver function when initiating valproic acid
diazepam MOA
bind GABA receptor - enhanced Cl influx
stimulate inhibitor membrane potentials
lorazepam vs. diazepam
lorazepam - less lipophilic
-longer duration of action
tx status epilepticus
diazepam and lorazepam
DOC for partial seizures and secondary generalized
carbamazepine
lamotrigine
oxcarbazepine
levetiracetam
DOC for primary generalized tonic-clonic seizures
valproate
lamotrigine
levetiracetam
DOC for absence seizures
ethosuximide
valproate
DOC for atypical absence, myoclonic, atonic seizures
valproate
lamotrigine
levetiracetam
increased suicide
patients on AEDs
mother taking AED
increased risk congenital malformations
16yo F, convulsion, to ER, grand mal in ER
drug choice?
carbamazepine - 1st line
phenytoin - side effects - coarse facial features, gingival hyperplasia, hirsutism, osteomalacia
60yo F - warfarin therapy, complex partial seizures
-first on carbamazepine - switched to levetracetam
get epistaxis
why?
carbamazepine - enzyme induction - so had increased warfarin dose
when stopped drug - also needed to decrease warfarin dose
25yo M, ER, status epilepticus
- on carbamazepine
- drug tx?
lorazepam - long acting - compared to diazepam
also IV phenytoin, benzo, phenobarb