Pharmacology of Anticonvulsants Flashcards
How does lamotrigine work?
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?
Side effects:
Common: Rash, drowsiness
Less common but serious: Steven-Johnson’s syndrome, suicidal thoughts
What is an important fact about lamotrigine?
Introducing lamotrigine gradually is one of the keys to reducing the frequency and severity of allergic skin reactions.
How does sodium valproate work?
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 drug target of sodium valproate?
GABA transaminase
What are the side effects of sodium valproate?
Side effects (MANY):
Common: Stomach pain and diarrhoea, drowsiness, weight gain, hair loss
Serious: Hepatotoxicity, teratogenicity, pancreatitis
What is a fact about sodium valproate?
Broad CYP enzyme inhibitor - increases serum concentration of many co-administered drugs
How does diazepam work?
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 side effects of diazepam?
Side effects:
Common: Drowsiness, respiratory depression (if i.v. or at high dose)
Uncommon but serious: Haemolytic anaemia, jaundice
What are 2 facts about diazepam?
Main reason that diazepam is not used for long term suppression of seizures is due to the development of tolerance.
Diazepam is a Schedule 4 controlled drug - addiction prone individuals more likely to become dependent on diazepam.
How does levetiracetam work?
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 drug target of levetiracetam?
Synaptic vesicle protein SV2A
What are side effects of levetiracetam?
Common: dizziness, somnolence, fatigue and headache
