5. Anticonvulsants - Other Antiseizure Drugs

Front 1

How can you remember all the other Antiseizure drugs?

Back 1

Can The Force of Gravity Pull The Levetating Zona Lower?

Front 2

What is Can The Force of Gravity?

Back 2

-Clonazepam
-Topiramate
-Felbamate
-Gabapentin

Front 3

What is Pull The Levetating Zona Lower?

Back 3

-Pregabalin
-Tiagabine
-Levetiracetam
-Zonisamide
-Lamotrigine

Front 4

What class of drug is Clonazepam?

Back 4

A Benzodiazepine

Front 5

What is the mechanism of action of the benzodiazepines?

Back 5

GABA-A agonists - enhance the Chloride influx to inhibit the cell via hyperpolarization.

Front 6

What benzodiazepine is used for treating Status Epilepticus?

Back 6

Diazepam

Front 7

How is Diazepam administered when used for treating Status Epilepticus?

Back 7

By IV, along with Fosphenytoin to achieve seizure control once the continuous status epilepticus has been stopped.

Front 8

What is Clonazepam used for in treating seizures?

Back 8

Absence seizures and some types of Myoclonic seizures

Front 9

Why is Clonazepam used for treating absence/myoclonic seizures?

Back 9

Because it is a much longer acting benzodiazepine

Front 10

Why is Clonazepam not a firstline drug for treating absence or myoclonic seizures?

Back 10

-It has sedative side effects
-Repeated dosing induces tolerance

Front 11

How are all the OTHER antiseizure drugs often used?

Back 11

As ADJUNCTS - especially for treating partial seizures.

Front 12

Are these other antiseizure drugs always used as adjuncts?

Back 12

No, they're also used as monotherapeutic agents

Front 13

What is the mechanism of Felbamate?

Back 13

Antagonist of the glycine site on the NMDA receptor

Front 14

What is the NMDA receptor?

Back 14

A voltage-dependent receptor whose natural substrate is Glutamate and is only open when other receptors like Kainate rec have been activated

Front 15

What happens to the NMDA receptor when the Kainate receptor is activated and the neuron is depolarized?

Back 15

Mg plug stops blocking the NMDA receptor site for Glutamate and allows for it to bind.

Front 16

If Glutamate is the natural substrate of the NMDA receptor, what does Glycine have to do with it?

Back 16

Glycine acts at a modulatory site on the NMDA receptor to allosterically facilitate the action of Glutamate

Front 17

So what does Felbamate do to the NMDA receptor?

Back 17

Blocks the Glycine modulatory site to decrease the efficiency of this seizure-related NMDA receptor

Front 18

What is the bottom line result of Felbamate inhibiting NMDA receptors?

Back 18

It decreases excitation

Front 19

So what is the Clinical Use of Felbamate?

Back 19

Partial seizures that are refractory to other agents

Front 20

Why is Felbamate limited to treating only partial seizures that are refractory to other drugs?

Back 20

Because it can cause
-Aplastic anemia
-Hepatic failure

Front 21

What is one of the safest "other" antiseizure meds?

Back 21

Gabapentin

Front 22

What is the structure of Gabapentin?

Back 22

A structural analog of GABA

Front 23

What is the mechanism of action of Gabapentin?

Back 23

We don't know - but it does NOT act at GABA receptors.

Front 24

What is the clinical use of Gabapentin?

Back 24

Partial seizures w/ or w/out 2ndary generalized tonic-clonic seizures

Front 25

Why is Gabapentin so safe?

Back 25

Because it is NOT metabolized and it has NO protein binding so it will not interact with other drugs.

Front 26

What are 2 clinical uses in addition to the antiseizure mechanisms of Gabapentin?

Back 26

-Neuropathic pain
-ALS

Front 27

What drug is a structural analog of gabapentin?

Back 27

Pregabalin

Front 28

How is Pregabalin different from Gabapentin?

Back 28

It is more potent and may interact with voltage-gated Calcium channels

Front 29

What are the clinical uses of Pregabalin?

Back 29

-Adjunct therapy for Partial seizures
-Management of Neuropathic pain in diabetes/postherpetic neuralgia and fibromyalgia

Front 30

What drug acts very much like phenytoin and blocks repetitive AP's and may block Na channels?

Back 30

Lamotrigine

Front 31

What is the clinical use of Lamotrigine?

Back 31

-Partial seizures
-Absence seizures
Monotherapy has been approved

Front 32

What condition is Lamotrigine also used for treating?

Back 32

Bipolar disorder

Front 33

What is a serious side effect that Lamotrigine can cause?

Back 33

Rash including Stevens-Johnson syndrome

Front 34

What anti-seizure drug is derived from D-fructose?

Back 34

Topiramate

Front 35

What is Topiramate's mechanism of action?

Back 35

-Blocks Kainate-AMPA-type Glutamate receptors
-Enhances GABA effects

Front 36

So what general effect does Topiramate have on neurotransmission?

Back 36

Inhibits excitatory transmission

Front 37

And How does Topiramate inhibit excitatory transmission?

Back 37

By antagonizing the ability of AA's to activate the Kainate/AMPA subtype of glutamate receptor

Front 38

What is the mechanism of seizures that is blocked by Topiramate?

Back 38

The SPREAD of seizures - not the start of them

Front 39

So what are the 2 clinical uses of Topiramate?

Back 39

-Adjunct therapy for adults with partial seizures
-Prevention of migraines (a major use!)

Front 40

What drug that is used as an adjunctive treatment for partial seizures acts by blocking GABA uptake?

Back 40

Tiagabine

Front 41

What effect does Tiagabine's blocking GABA uptake have on seizures?

Back 41

It increases the inhibitory GABA in the synapse, thus causes more inhibition

Front 42

What partial seizures can be treated with these partial seizure adjunct drugs?

Back 42

Both complex and simple

Front 43

And what are complex and simple partial seizures again?

Back 43

Complex - cause a loss of consciousness
Simplex - no loss of consciousness

Front 44

What are the 2 clinical uses of Levetiracetam?

Back 44

-Adjunct tx of partial seizures
-Adjunct tx of myoclonic seizures

Front 45

Why is Levetiracetam safe?

Back 45

It has few drug interactions

Front 46

What is a newer drug for partial seizures in adults?

Back 46

Zonisamide

Front 47

What is the mechanism of action of Zonisamide?

Back 47

-Inhibits T-type calcium channels
-Inhibis Sodium channels

Front 48

So what does Zonisamide do to siezures?

Back 48

Stops their spread AND suppresses their foci!

Front 49

What are 2 adverse side effects of Zonisamide?

Back 49

-Ataxia
-Speech impairment

Front 50

So what is the present clinical use of Zonisamide?

Back 50

Adjunctive treatment for partial seizures in adults

Front 51

Since so many antiseizure drugs cause drug interactions, why would you want to give two together as adjunct therapies?

Back 51

To lower the dose of drugs that have dose-related side effects

Front 52

What is the best way to start out treatment for seizures?

Back 52

Start out with monotherapy - one drug

Front 53

If that drug doesn't work, what should you do?

Back 53

Try another drug

Front 54

If the other drug doesn't work what should you do?

Back 54

Then try 2 drugs together