Anti-Seizure Drugs- GK Flashcards
What is the difference between epilepsy & seizures? Describe the differences.
difference = duration of symptoms
Epilepsy: chronic, recurrent
Seizures: Finite, resolves
A transient disturbance of cerebral function due to an abnormal paroxysmal neuronal discharge in the brain.
What is this?
Seizure
Which drugs lower seizure threshold?
- theophylline
- alcohol
- high dose phenothiazines (anti-psychotics)
- antidepressants (esp bupropion)
- street drugs
What is the goal of treatment with anti-seizure medication?
- eliminate symptoms (seizures) with minimal side effects
- complete seizure freedom
______-_____% of pts may not be free from seizures and seizure control must be balanced with ___goals
20-35
QOL
When do we initiate therapy?
- no risk factors, normal MRI, normal EEG
- if risk factors present
- pts who have had 2 or more unprovoked seizures
Probability of a second seizure is less than 10% in the first year and approximately 21% by the end of 2 years
This is true for what type of pts?
pts with no risk factors, normal MRI, normal EEG
It is critical to establish an accurate diagnosis of the _________ and ________
seizure type
epilepsy classification
It is estimated that up to ____% of patients with epilepsy are nonadherent to medication.
60
T/F: Monotherapy is preferred for pts with seizures.
TRUE
When should you consider stopping pt on meds?
Factors favoring successful withdrawal of ADS:
- seizure free period of 2-4 years
- complete seizure control within 1 year of onset
- onset of seizures between 2-35y/o
AND
normal neurologic examination and EEG
What are the 3 mechanisms of action of ASD?
- Modifies ionic conductance (Na+, Ca++, K+)
- dimunition of glutamatergic transmission ( dec excitatory)
- Enhancement of GABAergic transmission (inc inhibitory)
Glutamate is a ______ transmission
excitatory
GABA is a ______ transmission
inhibitory
The ultimate effect is to inhibit the local generation of seizure discharges by what 2 mechanisms?
- Reduce ability of neurons to fire action potentials at high rate
- reduce neuronal synchronization
Which drugs diminish glutamate release at the presynaptic cleft?
- Phenytoin
- fosphenytoin
- carbamazepine
- oxcarbazepine
- eslicabazepine acetate
- lamotrigine
- lacosamide
- ethosuximide
- retigabine
- levetiracetam
- brivaracetam
- gabapentin
- gabapentin enacarbil
- pregabalin
- perampanel
- valproate
- felbamate
- adrenocorticotropin
POSSIBLY
- topiramate
- zonisamide
- rufinamide
Which drugs act on the voltage gated Na+ channels at the presynaptic cleft?
- phenytoin
- carbamazepine
- lamotrigine
- lacosamide
POSSIBLY
- topiramate
- zonisamide
- rufinamide
Which drug acts on the voltage gated Ca++ channels (T-type) at the presynaptic cleft?
ethosuximide
Which drug acts on the voltage gated K+ channels at the presynaptic cleft?
Retigabine (ezogabine)
Which drug inhibits the release of glutamate by binding to SV2A?
Levetiracetam

Which drugs inhibit the release of glutamate by binding to the a2S subunit of P/Q type Ca++ channel?
gabapentin, pregabalin

Which drug targets the post-synaptic ionotropic glutamate receptor AMPA?
PerAMPAnel
Perampanel
What drugs with a mixed/unknown MOA target the post-synaptic receptors?
- Valproate
- felbamate
- topiramate
- zonisamide
- rufinamide
- adrenocorticotropin
Which drugs enhance GABA inhibition?
- Phenobarbital
- primidone
- benzodiazapines (diazepam, lorazepam, clonazepam)
- tiagabine
- vigabatrine
POSSIBLY
- topiramate
- felbamate
- ezogabine
Which drugs enhance GABA by working on the GABAa receptor?
- phenobarbital
- primidone
- benzodiazipines
POSSIBLY
- topiramate
- felbamate
- ezogabine
Which drug enhances GABA by working on (blocking) the GAT-1 GABA transporter?
Tiagabine
Which drug enhances GABA by working on (blocking) GABA transaminase?
Vigabatrin
When GABA interacts at two sites between alpha and beta subunits, what channel does it trigger?
Triggers chloride channel opening
Between what sites do benzos bind at?
between alpha and gamma subunits
When benzos bind at a single site between alpha and gamma subunits, this facilitates the opening of the _____________.
Which benzos specifically?
chloride ion channel
Diazepam, Lorazepam
__________ is a benzo antagonist
flumazenil
Binding sites of benzos are distinct from those of the ________
barbituates
What 3 drugs can treat a newly diagnosed generalized absence?
- ethosuximide
- lamotrigine
- valproic acid
What drugs can be used as alternatives for refractive absence?
- clonazepam
- topiramate
T/F: gabapentin is ineffective for new diagnosed generalized absence
TRUE
Ethosuximide MOA
blocks voltage gated Ca++ channels (T-type)
decreases glutamate
Clinical Application of Ethosuximide
Generalized absence
P-kinetics and interactions of Ethosuximide
long half-life
ADE of Ethosuximide
Headache
Blood dyscrasias
GI distress
HA
Ataxia
Drowsiness
Rash
Chronic: behavior changes
Lamotrigine MOA
Blocks voltage gated Na+ channels
decreases glutamate
Lamotrigine Clinical applications
generalized absence
generalized tonic-clonic
focal aware/impare
focal or generalized myoclonic
Lamotrigine has many ______
drug interactions
Lamotrigine ADEs
**Box warning: serious skin rash- start low & go slow
**Diplopia
HA
dizziness
hemophagocytic lymphohistiocytosis (HLH)
Valproate/ Valproic Acid MOA
mixed/unknown
increased GABA
or
enhances GABA action
or
mimics at post synaptic receptors
Valproate/Valproic Acid Clinical Applications
generalized tonic-clonic
generalized absence
focal aware/impaired
focal/generalized myoclonic
Valproate/Valproic Acid ADEs
hepatotoxicity, teratogenic, pancreatitis, alopecia
Clonazepam MOA
enhance GABA-A receptor responses
Clonazepam clinical applications
generalized absence
focal/generalized myoclonic
infantile spasms
Clonazepam P-kinetics/ interactions
>80% availability
Clonazepam ADEs
sedation
Topiramate MOA
mixed/unknown
AMPA receptor inhibitor
possibly blocks VG-Na+
enhances GABA activity
Topiramate Clinical Applications
generalized absence
generalized tonic-clonic
focal aware/impaired
migraine
Topiramate P-kinetics/interactions
both hepatic and renal clearance
Topiramate ADEs
Cognitive slowing
confusion
sleepiness, GI sx, metabolic acidosis, pregnancy cat D
Which 4 drugs do you want to avoid in tx of absence seizures?
carbamezapine
vigabatrin
gabapentin
tiagabine
What 2 meds are ineffective in tx of absence seizures?
Phenytoin
Phenobarbital
What are the 4 FDA approved meds to treat tonic-clonic seizures?
Lamotrigine
Levatriacetam
Perampanel
Topiramate
“The FDA Lama Levetated Per Toby’s request”
What happens during the tonic phase of the generalized tonic-clonic seizure?
- epileptic cry
- cyanosis
- incontinence
- generalized stiffening of body and lumbs, back arched
What happens during the Clonic phase of the generalized tonic-clonic seizure?
- salivary frothing
- cyanosis
- eyes blinking
- clonic jerks of limbs, body and head
What takes place during the post-ictal confusional fatigue phase?
limbs and body limp
- LOC/fainting 30 sec- 5 min
- general muscle contraction and rigidity 15-20 sec
- violent rhythmic muscle contraction and relaxation
- biting the cheek/tongue, clenched teeth/jaw
- incontinence
- stopped breathingor difficulty breathing during seizure
- cyanosis
What kind of seizure does this describe?
Generalized tonic-clonic seizure
What was given historically to pts who experienced generalized c-t seizures?
Phenytoin
carbamezapine
phenobarbital
valproid acid
Levetiracetam MOA
Blocks synaptic release machinery (SV2A)
decreases glutamate
Levetiracetam Clinical app
generalized t-c
focal aware/impaired
Levetiracetam has minimal drug interactions
T/F?
True
Levetiracetam ADEs
Behavioral problems
HA
sedation
seizures-focal onset
weakness
Carbamezapine MOA
Blocks V-G Na+ channels
decreases glutamate
Carbamezapine Clinical applications
generalized tonic-clonic
focal aware/imparied
Carbamezapine P-kin and interactions
many drug interactions
induces own metabolism
Carbamezapine ADEs
_***Box warning:_ serious derm rxns & HLA-B* 1502 allele (TEN; SJS) in Asians
Aplastic anemia & agranulocytosis
Ataxia
Diplopia
Hyponatremia
Metabolic Bone Disease (MBD) (Vit D and Ca++)
What is an alt to carbamezapine that you can use for focal onset seizures?
What is diff about this drug?
Oxcarbazepine
shorter 1/2 life
active metabolite
longer duration
fewer interactions reported
Lacosamide MOA
Blocks voltage gated Na+ channels
dec glutamate
Lacosamide Clinicall applications
Generalized t-c seizures
focal aware/impaired
Lacosamide ADE
small increase in PR interval
dizziness
headache
nausea
Phenytoin MOA
blocks voltage gated Na channels
dec glutamate
Phenytoin Clinical app
Gen t-c
focal aware/impaired
Phenytoin p-kin and interactions
_***Box warning: CV risk w/rapid infusion_
variable absorption, dose-dependent elimination, protein binding, many drug int.
Phenytoin ADE
ataxia
nystagmus
gingival hyperplasia
hirsutism
neuropathy
folate deficiency
MBD
Phenobarbital MOA
Enhances GABAa receptor responses
Phenobarbital Clinical app
gen t-c
focal aware/impaired
Phenobarbital p-kin and interactions
long 1/2 life
inducer of P450
many interactions
Phenobarbital ADEs
sedation
intellectual blunting
MBD
behavior changes
ataxia
Gabapentin MOA
blocks synaptic release machinery A2S
dec glutamate
Gabapentin Clinical applications
gen t-c
focal aware/impaired
Gabapentin p-kin and interactions
variable bioavailability
renal elimination
Gabapentin ADEs
ataxia
somnolence
weight gain
dizziness
What are the 6 FDA approved drugs for Focal onset (partial) seizures?
Carbamazepine
Lacosamide
Phenobarbital
Phenytoin
Topiramate
Valproic Acid
“Carbs lack phenophen topval”
What 3 drugs can be used in focal onset (partial) seizures as refractory monotherapy or adjunct?
Pregabalin
Vigabatrin
Perampanel
Pregabalin MOA
Blocks synaptic release machinery A2S
decreases glutamate
Pregabalin Clinical app
focal aware/impaired
Pregabalin P-kin and interactions
renal elimination
Pregabalin ADEs
ataxia
somnolence
weight gain
dizziness
Vigabatrin MOA
GABA transaminase enhancing GABA activation
Vigabatrin clinical app
focal aware/impaired
Vigabatrin p-kin and interactions
renal elimination
Vigabatrin ADEs
_**Box warning: permanent vision loss_
drowsiness, dizziness, psychosis, ocular effects
MOA: blocks postsynaptic ionotropic glutamate receptors AMPA, dec glutamate
Clinical app: focal aware/impaired
P-kin: multiple metabolites with long 1/2 lifes
Interactions: substantial, with increased clearance caused by CYP3A
What drug?
Perampanel
What drugs would you use for myoclonic seizures?
FDA approved:
levatriacetam
Alt:
Clonazepam
Topiramate
Valproic Acid
Zonisamide
Drugs with minimal or rare interactions
Gabapentin
Levetiracetam
Pregabalin
Vigabatrin