Anti-Epileptics (the Rest)

Question 1

What is the MOA of Felbamate?

Answer 1

Use dependent block of NMDA glutamate receptors, (these receptors need both glutamate and glycine to work), as well as potentiating the GABA subtype A mediated inhibition.

Question 2

What is THE THING to remember about Felbamate? When would we even use Felbamate?

Answer 2

Unexpectedly high rates of APLASTIC ANEMIA and SEVERE HEPATITIS, and for this reason INFORMED CONSENT MUST BE OBTAINED. We would only use this drug if pt is refractory to other tx.

Question 3

Tx of Felbamate?

Answer 3

If patient is refractory to other tx. It tx partial seizures, seizures associated with Lennox and Gestaut syndrome.

Question 4

When is Felbamate CI-ed?

Answer 4

In patients with blood dyscracia history or liver disease (due to severe AE’s of aplastic anemia and severe hepatitis).

Question 5

What is the MOA of Gabapentin/Pregabalin?

Answer 5

Blocks Voltage gated Ca channels in the pre synapse (this is NOT the T-type Ca channels) and as a result there is a decrease in the release of excitatory neurotransmitters like glutamate.

Question 6

What are the seizure and non seizure uses of gabapentin and pregabalin?

Answer 6

Adjunct use in partial seizures, and non seizure use is for neuropathic pain (pregabalin has additional neuropathic pain application).

Question 7

What are the AE’s of gabapentin and pregabalin?

Answer 7

Minor, sedation, dizziness, weight gain, peripheral edema.

Question 8

Preggo and DDI of gabapentin and pregabalin?

Answer 8

Not enough info for preggo study, and no known metabolite DDIs.

Question 9

What is the MOA of Lamotrigine?

Answer 9

Inhibition of VG Na channels, somehow inhibits glutamate release, and seems to have some effect of 5-HT3 inhibition (but we’re not sure if this matters).

Question 10

Tx use of Lamotrigine?

Answer 10

Broad spectrum, so generalized, partial, myoclonic, Lennox-Gestaut. Can also be used for bipolar.

Question 11

What’s special about the AE’s of Lamotrigine?

Answer 11

It causes the usual annoyances like headaches nausea dizziness ataxia anxiety insomnia migranes, etc etc. However, there is NO SEDATION OR COGNITIVE SIDE EFFECTS!!! It also has the more serious side effects like SJS and TEN, but usually skin rashes caused by this drug is the non serious variety. Aseptic meningitis possible but rare. Drug seems to accumulate in melanin rich tissues but why that matters is unknown.

Question 12

Preggo and Lamotrigine?

Answer 12

No data, hasn’t shown to be teratoginic thus far.

Question 13

DDIs of Lamotrigine?

Answer 13

Phenytoin, Carbamazepine and Phenobarbitol induces metabolism of Lamotrigine. Valproic acid on the other hand inhibits Lamotrigine metabolism. Lamotrigine inhibits DHF reductase so use of Folate Inhibitors need caution.

Question 14

What is the MOA of Topiramate?

Answer 14

Moderate effect of blocking VG Na channels, but also depresses the excitatory action of the AMPA/Kainite glutamate receptors. It also acts on the GABA subtype A receptors to enhance the inhibitory effects of GABA. Most importantly, Topiramate INHIBITS CARBONIC ANHYDRASE, the clinical effects of this is unknown.

Question 15

Tx uses of Topiramate?

Answer 15

Broad spectrum anti-seizure (partial, generalized, L-G, absence). It can also be used for non seizure stuff like Px for migranes, cluster headaches, and neuropathy.

Question 16

What are the effects of the Carbonic Anhydrase Inhibotory AE of Topiramate?

Answer 16

1. Acute myopia with secondary angle closure glaucoma.
2. Metabolic acidosis (because increase loss of bicarb in urine – carbonic anhydrase is required to recycle the bicarb – resulting in less serum bicarb = metabolic acidosis. 3. Increased risk of kidney stones.
3. Oligohydrosis/Hyperthermia, normal heat related perspiration becomes severely impaired.

Question 17

DDI’s of Topiramate?

Answer 17

Topiramate + Valproic acid = incerased risk of hyperammonimia and associated encephalopathy.

Question 18

How is Zonisamide associated with Topiramate?

Answer 18

They are both Carbonic Anhydrase inhibitors.

Question 19

What is the MOA of Levetiracetam?

Answer 19

Not sure, but perhaps binds to synaptic vesicle proteins SV2A –> might modify the synaptic release of glutamate and GABA through action on vesicular function.

Question 20

What are the Tx of Levetiracetam?

Answer 20

Partial seizures, generalized tonic/clonic, myoclonic. All adjunct.

Question 21

AE of Levetiracetam? DDI?

Answer 21

Well tolerated, minor stuff. Low DDI’s.

Question 22

If we want to use conventional AED’s, which would we use to tx partial seizures or complex partial seizures?

Answer 22

Carbamazepine, Phenyoin, Valproate.

Question 23

Which conventional AED’s would we use for partial with generalized tonic/clonic seizures?

Answer 23

Carba, Phenytoin, Valproate, as we would with simple or complex. But also Phenobarbitol and primidone.

Question 24

4 drugs to use for absence seizures?

Answer 24

Ethosuximide, Valproate, Cloazepam, and Lamotrigine.

Question 25

3 drugs to use for myoclonic seizures?

Answer 25

Valproate, Clonazepam, and Levetiracetam.

Question 26

9 drugs that can be used for tonic/clonic?

Answer 26

All the conventionals already mentioned (i.e. valproate, phenytoin, phenobarbitol, carbamazepine, primidone) but also Lamotrigine, Topiramate and Levetiracetam.

Question 27

4 drugs to use for status epilepticus? The 5th drug if all else fails?

Answer 27

All IV formulations of Lorazepam or Diazepam, or Phenytoin/fosphenytoin. Phenobarbitol if all else fails.

Question 28

5 drugs for L-G syndrome?

Answer 28

Valproic acid, Clonazepam, Lamotrigine, Topiramate, Felbamate.