pharmacology of anticonvulsants Flashcards
what is the primary action of lamotrigine
blocks voltage gated na+ channels preventing na+ influx. prevents depolarisation of glutamatergic neurones reduces glutamate excitotoxicity
what is the drug target of lamotrigine
voltage gates na+ channels
what are the main side effects of lamotrigine
common - rash, drowsiness
less common but severe - steven johnsons syndrome or suicidal thoughts
extra info on lamotrigine
introducing gradually is one of keys to reducing frequency and severity of allergic skin reactions
what is the primary action of sodium valproate
inhibition of gaba transaminase prevents breakdown of gaba. increases gaba concentrations directly in synapse pre synaptically also indirectly prolongs gaba in synapse.
what is the target of sodium valproate
gaba transaminase
what are the side effects of of sodium valproate
common - stomach pain, diarrhoea, drowsiness, weight gain, hair loss
serious - hepatotoxicity, teratogenicity, pancreatitis
extra info on sodium valproate
broad cyp enzyme inhibitor - increases serum conc of many co administered drugs
what is main action of diazepam
increases chloride ion influx in response to gaba binding at gaba a receptor. increases chloride ion influx associated with hyperpolarisation of excitatory neurones
what are the side effects of diazepam
drowsiness, respiratory depression,
uncommon but serious - haemolytic anaemia, jaundice
extra info on diazepam
not used for long term supression of seizures due to development of tolerance
what is the action of levetiracetam
inhibition of synaptic vesicle protein sv2a. inhibits this protein and prevents vesicle exocytosis. reduction in glutamate secretion reduces glutamate toxicity
target site of levetiracetam
synaptic vesicle protein sv2a
side effects of levetiracetam
common - dizziness, somnolence, fatigue, headache
extra info on levetiracetam
metabolism of drug has no effect on cytochrome p450 enzyme system so favourable in terms of long term drugs
drug target of diazepam
benzodiazepine site on gaba a receptor
what is the treatment for seizures dependant on
type of seizure
individual patients
what are the main goals of antiepileptic drugs
eliminate seizures/reduce frequency to max degree
avoid adverse effects associated with long term treatment
aid patients in maintaining normal lifestyles
first line treatment for absence seizures in boys/men and women of non child bearing potential
ethosuximide or sodium valproate
first line treatment for absence seizures in women of child bearing potential
ethosuximide
adjunctive treatment for absence seizures in boys/men or non child bearing potential women
combine ethosuximide, sodium valproate or lamotrigine
adjunctive treatment for absence seizures in women of child bearing age
combine ethosuximide and lamotrigine
first line treatment for boys/men/non child bearing potential women for focal seizures
carbamazepine or lamotrigine
first line treatment in child bearing potential women with focal seizures
carbamazepine or levetriracetam