Anticonvulsants Flashcards
How to diagnose epilepsy
Electroencephalography (EEG) or MRI
Summarise the fundamental causes of epilepsy/seizures
Due to either an increase in excitatory transmission or a decrease in inhibitory transmission
5 different seizure types?
Tonic-clonic seizures – loss of consciousness-> muscle stiffening-> jerking/twitching-> deep sleep-> wakes up
Absence seizures – brief staring episodes with behavioural arrest
Tonic/atonic seizures – sudden muscle stiffening/sudden loss of muscle control
Myoclonic seizures – sudden, brief muscle contractions
Status epilepticus – > 5 min of continuous seizure activity
What are Tonic-clonic seizures
loss of consciousness-> muscle stiffening-> jerking/twitching-> deep sleep-> wakes up
What type of seizure involves loss of consciousness-> muscle stiffening-> jerking/twitching-> deep sleep-> wakes up
Tonic-clonic seizures
What are Absence seizures
brief staring episodes with behavioural arrest
What type of seizure involves brief staring episodes with behavioural arrest
Absence seizures
What are Tonic/atonic seizures
sudden muscle stiffening/sudden loss of muscle control
What type of seizure involves sudden muscle stiffening/sudden loss of muscle control
Tonic/atonic seizures
What are Myoclonic seizures
sudden, brief muscle contractions
What type of seizure involves sudden, brief muscle contractions
Myoclonic seizures
What is Status epilepticus
> 5 min of continuous seizure activity
What type of seizure involves > 5 min of continuous seizure activity
Status epilepticus
Simple vs complex seizures
Simple – retained awareness/consciousness
Complex – impaired awareness/consciousness
What drugs are used for Status epilepticus
Diazepam
What drugs are used for Tonic/atonic seizures
Valproate
What drugs are used for Absence seizures
Ethosuximide
lamotrigine
valproate
What drugs are used for Tonic-clonic seizures
Carbazepine
lamotrigine
valproate
What drugs are used for myoclonic
levetiracetam
topiramate
valproate
What drugs are used for simple partial/complex partial seizures
carbamazepine
lamotrigine
levetiracetam
valproate
What drug is used in ALL forms of epilepsy
Sodium valproate
Glutamate receptors? (3)
NMDA, AMPA and kainate
What is SVA2
Synaptic vesicle associated (SV2A) protein allows vesicle attachment to presynaptic membrane
what is the name of the protein which allows vesicle attachment to presynaptic membrane
SVA2
families of drugs used as anti-convulsants?
VOLTAGE-GATED Na+ CHANNEL BLOCKER
VGCC blockers
Glutamate exocytosis inhibitors
Glutamate receptor antagonist
Example of VGSC antagonist
Carbamazepine or LAMOTRIGINE
Example of VGCC antagonist
Ethosuximide
Example of SV2A inhibitor?
Levetiracetam
Glutamate receptor antagonist
topiramate
topiramate is an example of a ….
Glutamate receptor antagonist
Levetiracetam is an example of a
SVA2 inhibitor
Ethosuximide is an example of a
VGCC antagonist
Carbamazepine is an example of a
VGSC antagonist
What type of seizures are VGSC antagonists indicated in
- Tonic-clonic seizures
What type of seizures are VGCC antagonist indicated in
- Absence seizures
What type of seizures are SVA2 inhibitor indicated in
- Myoclonic seizures
What type of seizures are glutamate receptor antagonists indicated in
- Myoclonic seizures
What type of seizures is sodium valproate good for
All
What type of seizures are BDZ good for?
status epilepticus
What type of drug is indicated for Myoclonic seizures
Glutamate receptor antagonist
What type of drug is indicated for status epilepticus
BDZ
What type of drug is indicated for Absence seizures
VGCC antagonists (and lamotrigine)
What type of drug is indicated for tonic-clonic seizures
VGSC antagonists
What type of drug is indicated for tonic/atonic
sodium valproate ONLY
What type of seizure is the only effective treatment sodium valproate
Tonic/atonic
What seizures is lamotrigine used for
Tonic-clonic
Absence
What seizures is valproate used for
All
What seizures is carbamazepine used for
Tonic clonic
What seizures is ethosuximide used for
Absence
What seizures is topiramate used for
Myoclonic
What seizures is diazepam used for
Status epilepticus
What seizures is levitarecetam used for
Myoclonic
What seizures is ONLY valproate used for
Tonic atonic
How does CARBAMAZEPINE work?
- Stabilises inactive state of Na+ channel, reducing neuronal activity
How does LAMOTRIGINE work?
- Inactivates Na+ channels by blocking® reducing glutamate neuronal activity
How does ETHOSUXIMIDE work?
- T-type Ca2+ channel antagonist ® reduces activity in relay thalamic neurones
How does LEVETIRACETAM work?
- Binds to synaptic vesicle associated protein (SV2A) ® preventing glutamate release
How does TOPIRAMATE work?
- Inhibits NMDA & kainate receptors
- Also affects VGSCs & GABA receptors
Onset and half life and indications of carbamazepine
- Onset of activity within 1 hour (FAST)
- 16-30-hour half-life (LONG)
Indications: - Tonic-clonic seizures; partial seizures
Onset and half life and indications of lamotrigine
- Onset of activity within 1 hour (FAST)
- 24-34-hour half-life (LONG)
Indications: - Tonic-clonic seizures; absence seizures
Onset and half life and indications of ethosuximide
- Long half-life (50 hours)
Indications: - Absence seizures
Onset and half life and indications of levetiracetam
- Fast-onset (1 hour); half-life (10 hours)
Indications: - Myoclonic seizures
Onset and half life and indications of topiramate
- Fast-onset (1 hour); long half-life (20 hours)
Indications: - Myoclonic seizures
Onset and half life and indications of valproate
- Fast onset (1h); half-life (12h)
Indicated for all
Onset and half life and indications of diazepam
- Rectal gel - Fast-onset (within 15 min); half-life (2 hours)
Indicated for status epiliticus
How does valproate work?
- Inhibits GABA transaminase increases GABA-mediated inhibition
- Means there is more GABA going around, also as GABA is metabolized to glutamate it means there’s less glutamate about
How does diazepam work?
- GABA receptor, PAM increases GABA-mediated inhibition
