Pharmacology of Epilepsy Flashcards
What is generalized tonic-clonic epilepsy?
Seizures characterized by a tonic stage (loss of consciousness, body stiffens) shortly followed by a second clonic stage (contraction and relaxation of muscles)
What is an absence seizure?
Seizure characterised by loss of awareness of surroundings, the patient may have a blank stare and will not respond
What is a myoclonic seizure?
brief, shock-like jerks of a muscle or a group of muscles
What is the drug target for Lamotrigine?
Voltage gated sodium channels
What is the primary mechanism of action of Lamotrigine?
Blocks voltage gated sodium channels preventing sodium influx. Prevents depolarisation of glutamatergic neurones and reduces glutamate excitotoxicity
What are the main side effects of Lamotrigine?
Rash and drowsiness. Suicidal thoughts
What is the best way to use Lamotrigine to prevent side effects?
Gradual introduction
What is the drug target for Sodium Valproate?
GABA transaminase
What is the primary mechanism of action of Sodium Valproate?
Inhibition of GABA transaminase prevents the breakdown of GABA, increasing GABA concentrations in the synapse.
What are the main side effects of the use of Sodium Valproate?
Stomach pain and diarrhoea, drowsiness, weight gain, hair loss. Hepatotoxicity, Teratogenicity and pancreatitis
What is the drug target for diazepam?
Benzodiazepine site on the GABA A receptor
What is the mechanism of action of diazepam?
Increases chloride ion influx in response to GABA binding to GABA A receptor causing hyperpolarisation of excitatory neurones
What side effects are associated with diazepam?
Drowsiness, respiratory depression, haemolytic anaemia, jaundice
Why is diazepam not used for long term supression of seizures?
Development of tolerance
What is the drug target for Levetiracetam?
synaptic vesicle protein SV2A
what are the therapeutic objectives of antiepileptic drug therapy?
to eliminate seizures or reduce their frequency, to avoid adverse effects associated with long term treatment
what is the primary mechanism of action of levetiracetam?
inhibition of synpatic vesicle SV2A preventing exocytosis, reducing glutamate excitability
what are the common side effects associated with levetiracem use?
dizziness, somnolence, fatigue and headache
what makes levetiracetam a favourable drug?
the metabolism of levetiracetam has no effect on cytochrome P450 enzyme so there is no drug-drug interactions
why is there a difference in the epileptic treatment between men and women?
Valproate causes neural tube defects, decreased IQ and autism after in utero exposure
What affect does taking the combined oral contraceptive pill (COC) have on lamotrigine?
coadministration of COC leads to reduced lamotrigine levels in the blood
