Anticonvulsants

Question 1

seizure

Answer 1

clinical manifestation of excessive hypersynchronous neuronal activity

Question 2

Two major excitatory NTs

Answer 2

aspartate and glutamate

Question 3

Two major inhibitory NTs

Answer 3

GABA and glycine

Question 4

epilepsy

Answer 4

enduring disorder characterized by recurrent seizures - a SYMPTOM

Question 5

cluster

Answer 5

2+ seizures in 24 hours

Question 6

status epilepticus

Answer 6

5+ minute seizure OR 2 or more seizures without return to consciousness

Question 7

refractory epilepsy

Answer 7

pharamcoresistant

Question 8

generalized

Answer 8

bilateral involvement, loss of consciousness

Question 9

tonic

Answer 9

increased muscle tone

Question 10

clonic

Answer 10

shaking/paddling

Question 11

focal

Answer 11

unilateral/regional signs, electric impulses from opposite hemisphere

Question 12

3 Components of a Seizure

Answer 12

1. Preictal
2. Ictal
3. Postictal

Question 13

Etiology Based Seizure Classification

Answer 13

1. Idiopathic
2. Structural

Question 14

What % of epilepsy patients are pharmacoresistant?

Answer 14

~25%

Question 15

4 Reasons Seizure Treatment May Be Required

Answer 15

1. Identifiable Structural Lesion or prior hx of brain dz/injury
2. Acute repetitive seizures or status epilepticus
3. Two or more isolated events within a six month period
4. Prolonged, severe, or unusual post-ictal events

Question 16

Objective of Anticonvulsant Therapy?

Answer 16

decrease the frequency, duration, and intensity of seizure (by about 50% or more)

Question 17

Are anti-convulsants lipid soluble?

Answer 17

yes, they need to cross the BBB

Question 18

Anticonvulsant MOAs

Answer 18

increase inhibition [of GABA or glycine] or decrease excitation [of aspartate and glutamate]

Question 19

Benzos are what schedule drug?

Answer 19

Schedule IV (controlled)

Question 20

Benzo MOA

Answer 20

targets postsynaptic GABA receptors to increase about of GABA in the synapse

Question 21

Benzo Examples

Answer 21

diazepam, clorazepam, midazolam, clorazepate, lorazepam

Question 22

Benzo Metabolism

Answer 22

liver

Question 23

Most common anticonvulsant in vet med?

Answer 23

phenobarbital

Question 24

At what level does phenobarb cause hepatotoxicity?

Answer 24

greater than 35 ug/mL

Question 25

3 Bloodwork Changes in Phenobarb Patients

Answer 25

1. Increased ALP 2. Low T4/High TSH 3. Hypertriglyceridemia

Question 26

Autoinduction

Answer 26

induces hepatic microsomal enzymes (P450) which reduces the half-life over time --> increased dosing or frequency may be required

Question 27

Can you use potassium bromide in cats?

Answer 27

NO

Question 28

Can you use phenobarb in cats?

Answer 28

yes (also autoinduction not a problem in cats)

Question 29

Bromide MOA

Answer 29

unclear but competes with chloride in the synapse to keep the membrane hyperpolarized

Question 30

Metabolism of Potassium Bromide occurs in what organ?

Answer 30

kidney!

Question 31

Do bromide and phenobarb have a wide or narrow therapeutic index?

Answer 31

narrow (monitor)

Question 32

psuedohyperchloremia

Answer 32

fake increase in serum chloride from benchtop analyzers because it can misidentify bromide as chloride

Question 33

Effect of Sodium on Bromide Therapy

Answer 33

high sodium diet means the patient will pee out all the bromide

Question 34

Side Effect of Bromide in Cats?

Answer 34

pneumonitis (irreversible)

Question 35

Bromidism

Answer 35

side effect of bromide therapy resulting in sedation, ataxia, tremors, and possibly pelvic limb paralysis

Question 36

Which anticonvulsant is a gastric irritant?

Answer 36

bromide

Question 37

Keppra MOA

Answer 37

bind to presynaptic vesicle SV2A to prevent glutamate release

Question 38

Keppra Metabolism

Answer 38

kidney

Question 39

Keppra Bioavailability?

Answer 39

100%

Question 40

Bloodwork Changes due to Keppra

Answer 40

NONE

Question 41

Side Effects of Keppra?

Answer 41

possible behavior change, transient sedation (~1 week), ataxia (in polytherapy)

Question 42

Keppra + Phenobarb

Answer 42

phenobarb will decrease the half-life of Keppra so those patients need a higher dose

Question 43

Which anticonvulsant may have an anti-kindling effect?

Answer 43

Keppra (neuroprotective properties that may decrease brain damage)

Question 44

Zonisamide MOA

Answer 44

post-synaptically increases GABA and presynaptically decreases glutamate

Question 45

Does zonisamide have a wide or narrow therapeutic index?

Answer 45

wide

Question 46

Bloodwork Changes for Zonisamide

Answer 46

none usually can have metabolic acidosis (since it binds to carbonic anhydrase in the RBCs)

Question 47

Pregabalin and Gabapentin MOA

Answer 47

presynaptic inhibits glutamate release by decreasing Calcium influx