Antiepileptics

Question 1

What is the mechanism of action of Carbamazepine?

Answer 1

Fast Na channel blocker

Carbamazepine is also known for its enzyme induction and autoinduction properties.

Question 2

What are the major adverse drug reactions (ADRs) associated with Carbamazepine?

Answer 2

-Delayed rash
-SIADH
-Blood dyscrasias
-Decreased bone density
-Toxicity: slurred speech, N/V, diplopia, tremor, drowsiness

HLA-B*1502 genotype is associated with increased risk of SJS.

Question 3

What is the therapeutic level of Carbamazepine?

Answer 3

4-12 mcg/ml

Question 4

What is the mechanism of action of Fosphenytoin?

Answer 4

Fast Na channel blocker

Fosphenytoin is a prodrug for phenytoin.

Question 5

What is the maximum administration rate for Fosphenytoin?

Answer 5

150 mg PE per minute

Question 6

What are the common ADRs of Gabapentin?

Answer 6

Sedation, respiratory depression increase with other CNS depressants

Question 7

What is the mechanism of action of Lacosamide?

Answer 7

Slow Na channel blocker

Question 8

What is a significant cardiovascular concern associated with Lacosamide?

Answer 8

PR prolongation or 1st degree AV block

Question 9

What is the mechanism of action of Lamotrigine?

Answer 9

Decrease glutamate and aspartate release; delays repetitive firing of neurons; block fast Na channels

Question 10

What are the major black box warnings (BBW) for Lamotrigine?

Answer 10

Rash/SJS/DRESS

Question 11

What is the mechanism of action of Levetiracetam?

Answer 11

Prevent hypersynchronization of epileptiform burst firing & propagation of seizure activity through binding at SV2A receptor

Question 12

What are the common ADRs of Levetiracetam?

Answer 12

-Depression
-Behavior changes
-Agitation
-Coordination difficulties
-Drowsiness

Question 13

What is the mechanism of action of Oxcarbazepine?

Answer 13

Fast Na channel blocker

Question 14

What is a notable side effect of Oxcarbazepine compared to Carbamazepine?

Answer 14

Hyponatremia > CBZ
Rash < CBZ (cross reactivity)
Blood dyscrasias < CBZ

Question 15

What is the mechanism of action of Phenobarbital?

Answer 15

Increase GABA-mediated chloride influx

Question 16

What is the therapeutic level of Phenobarbital?

Answer 16

15-40 mcg/ml

Question 17

What are the common ADRs of Phenytoin?

Answer 17

-Dose related: nystagmus, ataxia, drowsiness, cognitive impairment
-Non-dose related: gingival hyperplasia, hirsutism, acne, rash (DRESS), hepatotoxic
-Decrease bone density

Question 18

What is the maximum administration rate for Phenytoin?

Answer 18

50 mg/min due to arrhythmia, hypotension

Question 19

What is the mechanism of action of Pregabalin?

Answer 19

Inhibit subunit of voltage-dependent Ca channel

Question 20

What are the common ADRs of Pregabalin?

Answer 20

-Somnolence
-Behavioral problems
-Dizziness
-Weight gain
-Ataxia
-Angioedema

Question 21

What is the mechanism of action of Topiramate?

Answer 21

Fast Na channel blocker; enhance GABA; antagonize AMPA; carbonic anhydrase inhibitor

Question 22

What are the common ADRs of Topiramate?

Answer 22

-Drowsiness
-Paresthesias
-Weight loss
-Nephrolithiasis
-Psychomotor slowing
-Glaucoma
-Metabolic acidosis
-Word-finding difficulties
-Oligohidrosis

Question 23

What is the mechanism of action of Valproic acid?

Answer 23

Blocks T-type Ca current, block Na channel, increase GABA

Question 24

What are the major black box warnings (BBW) for Valproic acid?

Answer 24

-Hepatotoxicity
-Teratogenic
-Pancreatitis

Question 25

What is the therapeutic level of Valproic acid?

Answer 25

40-100 or 150 mcg/ml

Question 26

What is the mechanism of action of Zonisamide?

Answer 26

No effect on CYP

Question 27

What are the common ADRs of Zonisamide?

Answer 27

-Weight loss -Rash -Oligohidrosis -Somnolence -Agitation -Hallucinations -Metabolic acidosis -Nephrolithiasis

Question 28

What is the mechanism of action of Brivaracetam?

Answer 28

Unknown - high affinity for synaptic vesicle protein 2A

Question 29

What are the common ADRs of Cannabidiol?

Answer 29

-Hepatotoxicity -Sedation -Diarrhea

Question 30

What is the mechanism of action of Cenobamate?

Answer 30

Inhibit voltage gated Na channels, modulate GABA receptor

Question 31

What is a significant ADR associated with Cenobamate?

Answer 31

DRESS (titrate slowly)

Question 32

What is the mechanism of action of Clobazam?

Answer 32

Long acting benzo

Question 33

What are the common ADRs of Ethosuximide?

Answer 33

-Anorexia -N/V -Leukopenia -Agranulocytosis -Pancytopenia

Question 34

What is the mechanism of action of Felbamate?

Answer 34

Blocks glycine site on NMDA receptor

Question 35

What is the major concern when using Felbamate?

Answer 35

Hepatotoxicity, aplastic anemia (must sign consent)

Question 36

What is a major concern associated with Fenfluramine?

Answer 36

Serotonin syndrome with other serotonergic meds

Question 37

What is the mechanism of action of Ganaxolone?

Answer 37

Positive modulation of GABA receptor

Question 38

What are the common ADRs of Perampanel?

Answer 38

-Somnolence -Sedation -Dizziness -Fatigue

Question 39

What is the mechanism of action of Rufinamide?

Answer 39

Fast Na channel blocker

Question 40

What is a significant ADR of Rufinamide?

Answer 40

HA, dizziness, fatigue, nausea, somnolence (slow dose titration), rash (children)

Question 41

What is the mechanism of action of Tiagabine?

Answer 41

Block GABA uptake in presynaptic neuron

Question 42

What is the major concern associated with Vigabatrin?

Answer 42

BBW: Vision loss