antiseizure Flashcards
what is the 2nd most common neurological disorder
epilepsy
is epilepsy just 1 disorder
no, it encompasses many disorders
what characterizes epilepsy
recurrent seizures (chronic disease) - heretogenous symptom complex
what is a seizure
finite period of brain dysfunction resulting from abnormal discharge of cerebral neurons
what is an electroencephalogram
electrodes placed at standard positions on scalp to record field potentials caused by currents flowing as neurons in the brain fire APs
how do you figure out the degree of neural activity with electroencephalograms
you compare between pairs of electrodes (this allows a degree of localization of neuronal activity)
what are all seizures cause by
an imbalance between excitation and inhibition in brain
what is the mechanism of all seizures
they all differ
what are 2 types of partial seizures
simple and complex
what characterizes partial seizures
they have a localized onset
what are simple seizures like (3)
abnormal discharge with minimal spread - consciousness preserved
is consciousness preserved in simple partial seizures
yes
what are complex seizures like (4)
localized dischange with wide bilateral spread, usually limbic, loss of consciousness
is consciousness preserved in complex partial seizures
no
what is an aura
a sense that the seizure is starting
what are some weird things that can happen during complex seizures
altered consciousness. automatisms
what are automatisms and when do they happen (which seizure type)
fragmented behaviours (like lip smacking, swallowing…) - complex partial seizures
can you have a partial seizure that then generalizes to a tonic clonic seizures
yes
what are 5 types of generalized seizures
generalized tonic clonic, abence (petit mal), myoclonic jerks, atonic seizures, infantile spasms
what do generalized tonic clonic seizures look like
full blown attack with rigidity (tonic), followed by alternating relaxation and rigidity, and jerking of body (clonic)
what does Tonic mean
stiffening/rigidity
what does clonic mean
rhythmical jerking of body
how long does generalized tonic clonic seizure last
1-2 mins
what happens after a generalized tonic clonic seizure
postictal stupor (confused)
the drugs used for generalized tonic clonic seizure are similar to the drugs for which other seizures? which ones are they not similar to?
same for partial seizures and most general, but not absence
can you use similar drugs for generalized tonic clonic seizure and partial
yes
can you use similar drugs for generalized tonic clonic seizure and absence
no
what do absence seizures look like
staring, altered consciousness, sometimes mild jerking of eyelids and extremeties
what is the length and onset of absence seizures like
sudden onset, and brief
how often can absence seizures happen for some people
100s a day :(
what is the way to characterize absence seizures in EEG
3Hz spike
what are myoclonic jerks
symptoms of variety of seizures, but also an entity by itself
what is atonic seizure
sudden loss of postural tone, drops to floor
what are infantile spasms
heterogenous syndrome
whats a heterogenous syndrome
where there are many diff symptoms possible, not just one thing
what is associated with infantile seizures
mental retardation
how effective is treatment for infantile spasms
not great, drugs only effective in some patients and it doesnt help the mental retardation
what is an old antiseizure drug that is still used today in infantile spamsm
phenobarbital
how do most of the anti-seizure drugs nowadays work (3)
reduce sympathetic excitation, enhance synaptic inhibition, block ion channels
which 2 ion channels are a target for seizures
Na+ and Ca++
what do anti-seizure drugs do to the sodium channel (2)
prolong inactivation to make repetitive firing more difficult
which kind of seizures do drugs that target Na+ channels work well for
partial seizures
which 3 drugs affect sodium channels
phenytoin, carbamazepine, lamotrigine
what is the affinity for drugs that affect Na+ channels like
good affinity when they are open - helps block cells that are excessively reactive
which Ca++ channels are affected by anti-seizure drugs +what do they do to the activity
T-type calcium channels - suppressed activity
what is an example of a anti-seizure drug that supressed T-type ca channels
ethosuxamide
what does ethosuxamide do
block t type ca channel to stop oscillatory behaviour/ bursts
what kind of seizure is ethosuximide good for
absence
what do anti-seizure drugs want to do to GABA A receptors DIRECTLY
potentiate their action
what do anti-seizure drugs want to do to GABA A receptors INDIRECTLY
reduce GABA uptake or metabolism
which 2 drugs directly potential GABA A receptor action
benzos and barbs
which 3 drugs indirectly increase GABA levels
gabapentin, tiagabine, vigabatrin
how do gabapentin, tiagabine, vigabatrin block uptake of GABA
because they look a lot like it
what do you want to do to glutamate action with someone who has seizures
reduce
which 2 drugs reduce glutamate action
phenobarbital and topiramate
where does phenytoin act (which receptors)
Na+ K+ Ca++
what does phenytoin do to Na+ and K+ channel
block repetitive firing
what does phenytoin do to Na+ channel specifically
use dependent block
how does phenytoin do use dependent block of Na+ channel
it binds preferentially to inactive state of channel
what does phenytoin do to Ca+ AND what does this cause
blocks influx so there is less ca-dependent secretory processes
which kind of seizures in phenytoin best for
partial and generalized tonic clonic
which 3 drugs are good for partial and generalized seizures
phenytoin, carbamazepine, phenobarbital
what is the action of carbamazepine
similar to phenytoin (blocks K+ Ca+ Na+)
how is carbamazepine used as medication for seizures
first-line for partial, or combined with other drugs (like phenytoin)
what drug is used for trigeminal neuralgia
carbamazepine
what is the drug of choice for patients under 2yo
phenobarbital
how does phenobarbital work (2)
suppresses (heavily)excitatory transmission, potentiates GABA A receptor activation
what are 3 main drugs just for generalized seizures
ethosuximide
valproid acid
benzos
how does ethosuximide work
supresses T type Ca++ channels
what is the type of seizure that ethosuximide is best for
absence seizures
how is ethosuximide best for absense seizures
suppresses the characteristic 3Hz spike-and-wave
what is the mechanism of action for valproic acid
increase neuropeptide Y levels in brain
what kind of seizures is valproic acid good for (3)
absence, myoclonic, primary general tonic clonic
when are benzos good for seizures
for acute seizure, not for long term
why dont you want to use benos long term for seizures (2)
tolerance and sedation
what is the mechanism of action of vigabatrin (2)
irreversible inhibitor of GABA-transaminase (breaks down GABA) AND inhibits GABA transporter
what does GABA-transaminase do
breaks down GABA
what kind of seizures is vigabatrin good for
partial seizures
what happens with the amount of GABA near synapse with vigabatrin
increases
what is the mechanism of action of tiagabine
GABA uptake inhibitor (GAT-1)
what kind of course of treatment is tiagabine usually used
useful as adjunctive therapy, sometimes monotherapy
what is the mechanism of action of lamotrigine
like phenytoin on Na+, also Ca+ (blocks)
what kind of epilepsy is lamotrigine best used for
focalpartial epilepsy and absence
what kind of course of treatment is lamotrigine usually used
add on or monotherapy for focal/partial
what is the main drawback for lamotrigine
rash can be life threatening especially for kids!!!
what is the mechanism of action of felbamate
blocks NMDA on glycine sites (NR1 and NR2B)
what kind of seizure is felbamate best for
focal/partial
what is another name for focal seizures
partial
what kind of course of treatment is felbamate usually used
only as add on therapy
what are 2 really bad adverse effects for felbamate
aplastic anemia and severe hepatitis
which drug is good for refractory epilepsies and lennox-gasteaut syndrome
felbamate (its okay if you dont know)
what is the mechnamism of action for topiramate
inhibits Na+ channels, potentiates GABA effects, inhibits AMPA receptors
what kind of course of treatment is topiramate usually used
monotherapy
what is the unique structure like of topiramate
substituted monosaccharide
