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 are the main side effects of Lamotrigine?
Side effects:
Common: Rash, drowsiness
Less common but serious:
Steven-Johnson’s syndrome, suicidal thoughts
What is the target of Lamotrigine?
Voltage gated Na+ channels
How can you reduce the possible side effects of a skin rash when introducing Lamotrigine?
Introduce gradually
What is the mechanism of action of Sodium Valproate?
Inhibition of GABA transaminase prevents the breakdown of GABA. This increases GABA concentrations directly in the synapse presynaptically and also indirectly prolongs GABA in the synapse due to the fact that extraneuronal metanolism of GABA is slowed, which also slows GABA removal from the synapse.
What is the primary target of Sodium Valproate?
GABA transaminase
What are the main side effects of Sodium valproate?
Side effects (MANY):
Common: Stomach pain and diarrhoea, drowsiness, weight gain, hair loss
Serious:
hepatotoxicity, teratogenicity, pancreatitis
What do broad CYP inhibitors increase?
Serum concentration of many co-administered drugs
What is the 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 primary target of Diazepam?
Benzodiazepine site on the GABA A receptor
What are the main side effects of Diazepam?
Side effects:
Common: Drowsiness, respiratory depression (if i.v. or at high dose)
Uncommon but serious:
Haemolytic anaemia, jaundicE
Why is Diazepam not used long term?
Development of tolerance.
Who is more likely to become dependent on Diazepam?
Diazepam is a Schedule 4 controlled drug - addiction prone individuals more likely to become dependent on diazepam.
What is the mechanism of action of Levetiracetam?
Inhibition of the synaptic vesicle protein SV2A. It inhibits this protein and prevents vesicle exocytosis. A reduction in glutamate secretion is reduces glutamate excitotoxicity
What is the primary target of Levetiracetam?
Synaptic vesicle protein SV2A
