Pharmacology Of Epilepsy Flashcards
What is the primary mechanism of action of Lamotrigine?
Blocks voltage gated Na+ channels preventing Na+ influx
Prevents depolarisation of glutamatergic neurones and reduces glutamate excitotoxicity
What is the drug target of Lamotrigine?
Voltage gated Na+ channels
What are the main side effects of Lamotrigine?
Common:
- Rash
- Drowsiness
Less common but serious:
- Steven-Johnson’s syndrome
- Suicidal thoughts
How can the frequency and severity of allergic skin reactions associated with Lamotrigine be reduced?
By introducing Lamotrigine gradually
What is the primary mechanism of action of sodium valproate?
Inhibition of GABA transaminase -> prevents the breakdown of GABA
Increases GABA concentrations directly in the synapse, presynaptically and also indirectly prolongs GABA in the synapse as extra-neuronal metabolism of GABA is slowed -> slows GABA removal from the synapse
What is the drug target of sodium valproate?
GABA transaminase
What are the main side effects of sodium valproate?
Common:
- Stomach pain
- Diarrhoea
- Drowsiness
- Weight gain
- Hair loss
Serious:
- Hepatotoxicity
- Teratogenicity
- Pancreatitis
How can sodium valproate affect other co-administered drugs and why?
Increases serum concentration of many co-administered drugs as it is a broad Cytochromes P450 (CYP) enzymes inhibitor
What is the primary mechanism of action of Diazepam?
Increases choride ion influx in response to GABA binding at the GABA A receptor
Increased chloride ion influx associated with hyperpolarisation of excitatory neurones
What is the drug target of Diazepam?
Benzodiazepine site on the GABA A receptor
What are the main side effects of Diazepam?
Common:
- Drowsiness
- Respiratory depression (if i.v. or at high dose)
Uncommon but serious:
- Haemolytic anaemia
- Jaundice
Is diazepam used for long-term suppression of seizures?
No, because individuals can develop tolerance
Aside from side effects, what else must be considered when prescribing Diazepam?
Diazepam is a Schedule 4 controlled drug - addiction prone individuals are more likely to become dependent on diazepam.
What is the primary mechanism of action of Levetiracetam?
Inhibition of the synaptic vesicle protein SV2A - prevents vesicle exocytosis
Reduction in glutamate secretion reduces glutamate excitotoxicity
What is the drug target of Levetiracetam?
Synaptic vesicle protein SV2A
What does this EEG show?
Interictal epileptiform discharge (IED) - risk of seizure recurrence
