Chapter 4 - Epilepsy Flashcards Preview

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Flashcards in Chapter 4 - Epilepsy Deck (27)
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1
Q

What are the two main categories of seizures?

A

Focal (partial) seizures

Generalised seizures

2
Q

What types of seizures do ‘generalised’ seizured encompass?

A
Tonic-clonic
Tonic
Atonic
Myoclonic
Absence
3
Q

When initiating anti-epileptic treatment, what method should be taken to reduce the risk of adverse effects?

A

Titration - should start of low and then titrate upwards until seizure control is met

4
Q

If an anti-epileptic needs to be stopped or switched, how best should this occur?

A

Slowly titrating down and/or if initiating new anti-epileptic drug, this should also be titrated upwards slowly until seizure control has been met.

5
Q

Which two neurotransmitters are generally most commonly associated with excess excitation/ decreased inhibition of excited neuronal activity in the brain, causing seizures to occur?

A

Glutamate - excitory neurotransmitter
GABA - inibitory neurotransmitter

In epilepsy, there is an increase in glutamate action, causing consistent action potentials to be fired amongst neurones. GABA helps to inhibit this action.

6
Q

Anti-epileptics can be broadly categorised into 3 modes of action. What are these 3 categories?

A

1) Modulation of voltage-gated ion channels (target Na+ and Ca2+ channels)
2) Enhanced activity of synaptic inhibition (increased GABA activity)
3) Inhibition of synaptic excitement (decreased glutamate activity)

7
Q

Sodium valproate can be used for the treatment of which types of seizures?

A

All types

8
Q

Carbamazepine, Phenytoin, Lamtrogine are examples of anti-epileptics which have what MOA?

A

Act on voltage gated Na+ channels, to inhibit influx of Na+ ions into the pre-synaptic neurone — preventing depolarisation and therefore glutamate being released into the synaptic cleft and causing excitation of post-synaptic neuron

9
Q

Lamotrigine and ethosuximide are examples of anti-epileptics which have what MOA?

A

Act on voltage gated Ca2+ channels, to inhibit influx of Ca2+ ions into the pre-synaptic neurone — preventing depolarisation and therefore glutamate being released into the synaptic cleft and causing excitation of post-synaptic neuron

10
Q

How do benzodiazepines work to help control seizures?

A

Helps to potentiate the effects of GABA on GABA-A receptors — this consequently leads to an influx of Cl- ions into the post-synaptic neuron, causing replorarisation and therefore inhibition of excess excitation of neurons

11
Q

Which anti epileptic medicines need to be brand specific and patients are to be maintained on that specific brand?

A

Category 1:

Phenytoin
Carbamazepine
Phenobarbital
Primidone

12
Q

Which antiepileptic is associated with the highest teratogenic risk?

A

Sodium Valproate - highest risk of major and minor congenital malformations (in particular neural tube defects) and long term development disorders

13
Q

To reduce the risk of neural tube defects in renal patients with epilepsy who want to or are pregnant, what is advised to be prescribed?

A

Folic acid 5mg

14
Q

What is first line treatment for patients newly diagnosed with focal (partial) seizures?

A

Carbamazepine or lamotrigine ( lamotrigine is preferred)

15
Q

What is first line treatment for generalised tonic-clinic seizures?

A

Sodium valproate or lamotrigine

16
Q

What is first line treatment for absence seizures?

A

Ethosuximide or sodium valproate

17
Q

GABA analogues (Gabapentin and Pregabalin) may be used for what types of seizures? What other indication can they be used for?

A

Focal seizures

May also be used for neuropathic pain

18
Q

What else is carbamazepine licensed to be used for aside from epilepsy?

A

Trigeminal neuralgia

19
Q

Which type of seizure can lamotrigine exacerbate?

A

Myoclonic

20
Q

When initiating treatment with carbamazepine, eslicarbazepine, fosphenytoin or phenytoin, ethinicity plays an important part. Why?

A

In people of Han Chinese or Thai origin risk of drug induced Stevens-Johnson syndrome if the HLA-B*1502 allele is present

SCREENING for this allele in people of this origin is crucial if no other alternative therapy is available

21
Q

What serious side effects have been commonly reported or patients/ carers should be advised to look out for with carbamazepine, lamotrigine, oxcarbazepine and phenytoin?

A

Blood disorders

Patients should be reminded to report any signs of unexplained bleeding, bruising or signs of infection such as sore throat, malaise, fever etc

22
Q

What is the optimum plasma phenytoin concentration range?

A

10-20mg/L

23
Q

What monitoring requirements are needed for sodium valproate?

A

LFTs - hepatotoxicity has occurred with valproate use, especially in children under the age of 3

If hepatic dysfunction occurs treatment with sodium valproate should be stopped

24
Q

What specific side effects have been associated with topiramate use?

A

Acute myopia with secondary angle-closure glaucoma

25
Q

Midazolam can be used for status epilepticus but can also be used for conscious sedation. Why?

A

Fast onset of action and short duration of action which makes recovery period shorter than if other benzodiazepines were used

26
Q

Pancreatitis may develop as a result of which antiepileptic use?

A

sodium valproate

27
Q

What should patients be advised to report if taking Zonisamide?

A

Prevent and recognised signs of overheating and dehydration