Epilepsy

Question 1

What is epilepsy?

Answer 1

Disorder of brain function characterised by the periodic and unpredictable occurrence of seizures

Question 2

What does seizure mean?

Answer 2

Transient alteration of behaviour due to disordered,

Question 3

What are the main features of Epilepsy?

Answer 3

Neurotransmitter related CNS disorder
Cause often unknown
Can be caused by infection, tumours and head trauma
Generally well-controlled with pharmacotherapy

Question 4

What is the single common factor of this group of CNS disorder?

Answer 4

Excessively synchronous or sustained discharge of a group of neutrons in the brain

Question 5

What percentage of people with epilepsy do not respond well to drugs?

Answer 5

25%
50% respond well
25% require higher doses, may suffer side effects

Question 6

What are the two types of epilepsy?

Answer 6

Generalised

Partial

Question 7

Give some examples of generalised epilepsies?

Answer 7

Tonic-Clonic
Absence
Myoclonic
Atonic

Question 8

Give some examples of partial epilepsies

Answer 8

Simple
Complex
Secondary generalised

Question 9

What are the characteristics of a simple complex seizure?

Answer 9

Temporary localised motor movement

Question 10

What are the 4 classic drug target sites?

Answer 10

Receptor
Ion channels
Transport channels
Enzyme

Question 11

What is the drug target for diazepam?

Answer 11

Alpha sub-unit of the GABA Receptor
postsynaptic neurone in temporal lobe
diazepam binds to and increases GABA effectiveness at the receptor

Question 12

How does diazepam work?

Answer 12

enhanced chloride influx and hyper polarisation of the temporal lobe neurone
reduces the activity of post synaptic neutrons
benzodiazepines= positive allosteric modulators

Question 13

What is the drug target site for Lamotrigine?

Answer 13

VGSC’s 
Glutamatergic neurons in temporal lobe
Blocking Na+ channels 
Decreases depolarisation 
Decreases glutamate release 
Reduces stimulation of post-synaptic neuron

Question 14

How does Pregabalin work?

Answer 14

VGCC
Glutametergic neurons in temporal lobe
Blocking Ca channels 
Decreases Ca influx
Decreases vesicle exocytosis
Decreases Glutamate release
Reduces stimulation of postsynaptic neuron

Question 15

What is the drug target for Levetiracetam?

Answer 15

Synaptic vesicle protein
Presynaptic terminal of the glutamatergic neurons in temporal lobe
Interferes with vesicle fusion

Question 16

How does Tiagabine work?

Answer 16

Target: GABA reuptake receptors

Location: Presynaptic terminal of the GABAergic neurons in temporal lobe

Slowing of GABA inactivation

GABA remains in synapse for longer

Greater Cl- influx and hyperpolarisation

Question 17

How does Vigabatrin work

Answer 17

Target: GABA transaminase enyme

Location: presynaptic terminal of GABAergic neurones in temporal lobe

Inhibits GABA-T enzyme

GABA not effectively metabolised in the presynaptic terminal

Loss of conc. gradient for GABA reuptake from the synapse

GABA remains in synapse longer

Question 18

Why would Valporate not be prescribed?

Answer 18

Acts on multiple targets incl. VGSC’s, GABA-T, VGCC’c, NMDA receptors and may also enhance production of GABA

Higher propensity for side-effects due to hitting so many targets

Teratogenic