00:01
So once we've made a diagnosis and we've
evaluated the patient's seizure with EGG,
we need to treat the patient.
00:07
And what are some of the treatments
that we can consider in patients
with a diagnosis of
seizure or epilepsy?
Well, there are a lot.
00:14
And if we go through the
list it's quite long.
00:16
Phenobarbital, Primidone,
Phenytoin and Ethosuximide, Carbamazepine,
Valproic acid, Lamotrigine, Topiramate,
Oxcarbazepine, Levetiracetam,
Zonisamide, Pregabalin,
Lacosamide, Felbamate,
Rufinamide, Vigabatrin,
Tiagabine, Gabapentin.
00:34
And there are even more that are on this
list that I'm not even able to include
or newer agents that
are being developed.
00:39
The list is quite long,
and it would be very difficult to
go through the mechanism of action.
00:44
The potential side effects
and the seizure types
that are best treated with
each of these medicines
by just going through the
laundry list independently.
00:53
So when I'm thinking about
the seizure medicines,
I like to organize them by
their mechanism of action.
00:59
And we can see here
some of the categories
of these medications
by mechanism of action.
01:04
We'll start with
the GABAergic drugs.
01:07
This is a list of commonly
used antiepileptics
that act by increasing
GABAergic tone inhibitory tone.
01:15
Seizures occur because of
excess excitatory tone.
01:19
And the treatment here is in to
increase GABAergic or inhibitory tone.
01:24
And we can see those medicines
include phenobarbital,
primidone, the benzodiazepines,
and then to less commonly used medications
but in for important seizure
medicines, tiagabine and vigabatrin.
01:37
And each of these medicines act by
either binding at the GABA receptor
or increasing circulating GABA
neurotransmission in the brain,
increasing inhibitory tone.
01:47
The side effect of these
medicines is typically sedation,
that's one of the more common side effects
that we see with this class of medicines.
01:55
When we're increasing GABA
tone to reduce seizures,
we can increase inhibitory
tone throughout the brain,
and the side effect is sedation.
02:04
The second category that we see are
the sodium channel active agents.
02:08
Sodium is critical
in neurotransmission.
02:11
We saw that in when thinking
about the action potential
and the development of seizures.
02:17
And there's a list of medicines that act
primarily through sodium channel activity.
02:22
You can see phenytoin, carbamazepine,
oxcarbazepine, lamotrigine,
lacosamide,
topiramate and zonisamide
and each of these medicines has
a primary mechanism of action
through the sodium channels.
02:35
Sodium channel active agents
also has a list of side effects
that we see when attacking
the sodium channel.
02:41
And those are typically nausea,
vomiting, dizziness, ataxia or imbalance.
02:45
And sometimes cardiac issues,
which we can see here with lacosamide.
02:50
This group of medications
include some of the older
seizure medications like
phenytoin and carbamazepine
which have prominent
hepatic metabolism,
and then some of the newer
agents like oxcarbazepine,
lamotrigine, lacosamide,
topiramate, and zonisamide.
03:06
The third category we see are
the calcium channel activations.
03:10
And ethosuximide is probably the
prototypical calcium channel, active agent.
03:15
Ethosuximide acts on the
T-type calcium channels
and is important in primary
generalized epilepsies.
03:21
It's used to treat
absence epilepsy.
03:24
There's also 2 other medicines
that fall into this category
that you wouldn't think about,
and that's a gabapentin,
and pregabalin.
03:31
We typically think of these medicines
as increasing GABAergic tone,
increasing inhibitory
tone, and they do,
but they actually
don't act through GABA.
03:41
They act on the voltage-gated
calcium channels.
03:44
And so these 2 GABA drugs
act on the calcium channels,
but really worked to increase
inhibitory tone in the brain.
03:51
And so their side effects really
look more like the GABAergic agents,
then the calcium channel
agents like ethosuximide.
03:59
The next category of their
carbonic anhydrase inhibitors,
and this is not the mechanism
of their anti-seizure control.
04:05
But this is one of the important
side effects that is derived
from the carbonic
anhydrase activity
and that's topiramate
and zonisamide.
04:14
These medicines can act
at the renal tubules
and cause increase acid production
or acidemia, decreased sweating,
and they can be used
in some cases to reduce
CSF of production as in patients
with pseudotumor cerebri.
04:29
Levetiracetam acts through the
SV2A or synaptic vesicle protein.
04:34
This is a very novel
mechanism of action.
04:37
Levetiracetam is also often combined
with other seizure medicines
for rational polypharmacy
because it's really the only drug
that acts through this channel.
04:46
It is a very safe and well tolerated
medication with very few side effects.
04:50
Sedation we can see with
all anti-epileptics.
04:53
And about 5 to in some cases in kids 25% of
patients can have some problems with mood
and increased mood and irritability
or agitation with levetiracetam.
05:04
Valproic acid has many
mechanisms of action,
it doesn't really fit
well into a single bucket.
05:09
We see a number of side effects that
are both unique to valproic acid
and can be seen
with other agents.
05:14
Some of those unique valproic acid side
effects are weight gain or hair loss.
05:19
It can also cause
idiosyncratic pancreatitis.
05:21
So it's an important
medicine that we monitor.
05:23
And it is metabolized
hepatically through the liver,
and that's important
to monitor in patients
who are being treated with
valproic acid for any indication.
05:32
And then the last 2 categories are
the potassium channel active agents.
05:35
This is one of the newer
seizure medications "Potiga",
which acts to the potassium
channel in Q2 channel.
05:43
And then there are a couple of
other medicines that don't fall well
into a mechanism of action
specific categorization.
05:49
And that would be
felbamate and rufinamide.