Flashcards in Pharma 11.1 Epilepsy AEDs Deck (31):
1
what are the 2 types of generalised seizures?
absence and tonic-clonic
2
What occurs in an absence seizure?
staring, eyelid twitching, few muscle jerks. normal activity post attack
3
What occurs in a tonic-clonic seizure?
2 phases:
1) Tonic phase - body rigid, patient falls to floor, incontinence
2) clonic phase - convulsions, frothing at mouth, jerking of muscles
Followed by drowsiness, confusion or coma for several hours
4
What are the 2 types of partial seizures? What occurs in each of them?
Simple - conscious seizure
Complex - impaired consciousness, can become generalised
5
Define epilepsy
Tendency towards recurrent seizures
6
Define status epilepticus
Single convulsion lasting >30mins or convulsions ocurring back to back with no recovery
7
How can status epilepticus cause damage?
Physical injury due to fall, hypoxia, SUDEP
8
How can epilepsy be classified?
Primary - idiopathic
Secondary - known cause
9
What are some underlying causes which can result in epilepsy?
Brain tumours, pyrexia, alcohol or drugs or withdrawal, brain tumours, hypoglycaemia, brain injury
10
How would you take a history of a seizure?
Witness statements, pre, peri, and post seizure
11
What are the 4 types of AEDs?
Inhibition of glutamate release, inhibition of Ca channel, Inhibtion of Na channel, enhancement of GABA(A) action
12
What are the 3 types of inhibitiors of na channels?>
Lamotrigine, phenytoin, carbamezepine
13
What is the MoA of inhibitors of Na channels?
Only binds to channels in inactive state, preventing channels from returning to a resting state where they could continue to depolarise neurons. Preferentially binds high frequency discharge neurons
14
What are some ADRs of carbamezepine?
N&V, rashes, myelosuppression, dizziness, parasthesia, teratogenic
15
What are some ADRs of phenytoin?
Gingival hyperplasia, heaches, nystagmus, dizziness, hypersensitivity rashes, teratogenic
16
What are some ADRs of lamotrigine?
dizziness, ataxia, nausea, rashes,
17
What are the DDIs of the inhibitors of Na channels?
Phenytoin and carbamezepine - inducers of CYP450
Lamotrigine - oral contraceptives
18
What are the 2 types of enhancers of GABA action?
Valproate sodium, BZDs
19
Why is phenytoin used in emergency treatment?
Zero order kinetics - quickly reaches therapeutic levels
20
What is the MoA of valproate sodium?
Stimulates GABA synthesis and inhibits GABA inactivation
21
What is the MoA of BZDs
Positive allosteric modulation of GABARs.
22
Give an example BZD
lorazepam
23
What are some ADRs of valproate sodium?
ataxia, tremor, N&V, sedation, teratogenic
24
What are some ADRs of BZDs?
sedation, tolerance, confusion, aggresssion, resp and CNS depression, teratogenic
25
How would you prescribe an AED? What rules would you folow
aim for monotherapy, start low and increase dose to maximise effect and minimse ADRs
26
What AED would you use for primary generalised seizures?
Valproate sodium or lamotrogine
27
What AED would you use for partial seizures?
Carbamezepine or lamotrigine
28
What AED would you use for Status epilepticus?
BZD and IV phenytoin
29
What AED would you use in pregnancy and why? What other supplements would you combine it with?
Use lamotrigine - reduced teratogenic effects
Combined with folate and vit K supplements. Vit K reduces risk of cerebral hemorrhage and coagulopathy associated with AED-linked vit K deficiency. Folate reduces risk of neural tube defects
30
What would you do in an emergency involving status epilepticus?
1) ABC
2) lorazepam and then IV phenytoin
3) treat underlying cause
4) if all else fails, ITU referral with paralysis, sedation and intubation
31