18 - Epilepsy treatment

Question 1

What is the criteria to be diagnosed with epilepsy

Answer 1

Occurrence of at least one unprovoked seizure

Question 2

What are the two types of seizures

Answer 2

Focal

Generalised

Question 3

What is a focal seizure

Answer 3

Activation of neurons in a relatively small, discrete region

Question 4

What is a complex partial seizure

Answer 4

Impairment of consciousness

Question 5

What are the types of generalised seizures

Answer 5

Tonic
Atonic
Clonic
Tonic-clonic
Generalised absence seizures

Question 6

What are tonic seizures

Answer 6

Extension of the extremities

Question 7

What are atonic seizures

Answer 7

Sudden loss of muscle tone

Question 8

What are clonic seizures

Answer 8

Repetitive muscle twitching

Question 9

What are generalised absence seizures (petit-mal)

Answer 9

Brief lapse of consciousness

Question 10

What are 6 mechanisms of anticonvulsants

Answer 10

1) Enhance Na channel inactivation
2) Inhibit excitatory AA release (block Ca channels)
3) Block excitatory AA action
4) Enhance GABA action
5) Inhibit GABA breakdown
6) Inhibit GABA uptake

Question 11

What are Na channels critical for

Answer 11

Initiation and propagation of action potentials

Question 12

How do Na+ channel blockers work

Answer 12

• Enhance voltage-gated Na channel inactivation
• Use dependent
• Reduction of sustained high-frequency firing of action potentials

Question 13

What are some Na channel blockers

Answer 13

Phenytoin
Carbazepine
Lamotrigine

Question 14

What are some side effect of Na channel blockers

Answer 14

Dizziness
Upset stomach
Headache
Unsteadiness

Question 15

MOA of ethosuximide (Zarontin)

Answer 15

T-type Ca channel blocker

Question 16

What is ethosuximide used for

Answer 16

Treatment of generalised absence seizures

Question 17

What two drugs are Ca channel blockers

Answer 17

Levetiracetam

Ethosuximide

Question 18

What does levetiracetam bound to

Answer 18

Neuronal synaptic vesicle glycoprotein 2A which coordinates synaptic vesicle exocytosis
Inhibits presynaptic CaV channels

Question 19

What are some side effects of levetiracetam

Answer 19

Sleepiness
Loss of energy
Dizziness
Anxiety

Question 20

How do barbiturates work

Answer 20

1) Increase affinity for GABA
2) Increase Cl conductance
3) Prolongs the open time of the channel

Question 21

What are the unwanted sedative side effects of barbiturates

Answer 21

1) Tiredness, forgetfulness
2) Confusion, dizziness
3) Anaemia
4) Folic acid deficiency
5) Decreased libido, erection problems

Question 22

What is the MOA for benzodiazepines

Answer 22

Enhance the actions of GABA

Increases frequency of channel opening

Question 23

Which GABAA receptor subunits do benzodiazepines act at

Answer 23

a1, a2, a3, a5, y

Question 24

Where do benzodiazepines bind at

Answer 24

Interface between a and y

Question 25

What are some issues of benzodiazepines

Answer 25

1) Rapid tolerance 2) Sleepiness 3) Fatigue 4) Poor concentration

Question 26

How does vigabatrin work (Sabril)

Answer 26

Inhibit GABA breakdown Structural analogue of GABA Specific inhibitor of GABA transaminase

Question 27

What are some side effects of vigabatrin

Answer 27

Fatigue Dizziness Loss of peripheral vision

Question 28

What is the mechanism of tiagabine

Answer 28

Inhibition of GABA reuptake GAT1 inhibitor Increase extracellular GABA levels

Question 29

What are some side effects of tiagabine (Gabitril)

Answer 29

Sleepiness Tremor Dizziness Anxiety

Question 30

What is the MOA of sodium valproate

Answer 30

Enhance Na channel inactivation Block Ca channel Maybe: Inhibit GABA breakdown

Question 31

What are some side effects of sodium valproate

Answer 31

``` Dizziness Upset stomach Headache Tremor Weight gain Hair loss ```

Question 32

What is the MOA of topiramate

Answer 32

Enhance Na channel inactivation Block excitatory AA action (AMPA/Kainate receptor antagonist) Enhance GABA action

Question 33

What are some side-effects of topiramate

Answer 33

``` Dizziness Confusion Problems with word retrieval Tremor Weight loss Hair loss ```

Question 34

What is the MOA of felbamate

Answer 34

Enhance Na channel inactivation Block excitatory AA action (NMDA receptor antagonist) Enhance GABA action

Question 35

What are the MOAs of gabapentin and pregabalin

Answer 35

Unknown but increase total GABA concentrations Synthesised as GABA analogues Bind to a2d subunit of voltage-gated Ca channels

Question 36

What are the side effects of gabapentin and pregabalin

Answer 36

Sleepiness, weight gain and dizziness

Question 37

What is the GABRG2 mutation

Answer 37

Lysine 289 to methionine mutation in y2 subunit of GABAA receptor Decrease in GABAA receptor amplitude

Question 38

What is SCN1A mutation

Answer 38

Nav1.1 channel arginine 1916 to glycine mutation | Renders Nav1.1 non-functional