Epilepsy Flashcards
What are the drug (classes) used to manage epilepsy?
Lamotrigine
Sodium valproate
Diazepam
Levetiracetam
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 primary mechanism of action of Sodium valproate?
Inhibition of GABA transaminase, prevents the breakdown of GABA. Increases GABA concentrations directly in the synapse presynaptically. Indirectly prolongs GABA in the synapse.
What is the primary mechanism of action of Diazepam?
Increase chloride ion influx in response to GABA binding at the GABA A receptor. Increased chloride ion influx — hyperpolarisation
What is the primary mechanism of action of Levetiracetam?
Inhibition of the synaptic vesicle protein SV2A. Inhibits this protein and prevents vesicle exocytosis.
Reduction in glutamate secretion, reduces glutamate excitoxicity
What is the drug target of Lamotrigine?
Voltage gated Na+ channels
What is the drug target of Sodium Valproate?
GABA transanimase
What is the drug target of Diazepam?
Benzodiazepine site on GABA A receptor
What is the drug target of Levetiracetam?
Synaptic vesicle protein SV2A
What is seen in the EEG of a person wtih Generalised Tonic - Clonic seizures?
interictal epileptiform discharge - delayed spikes
What is the main side effect of Lamotigrine?
Common: Rash, Drowsiness
Serious: SJS, Suicidal Thoughts
What is the main side effect of Diazepam?
Common: Drowsiness, Respiratory Depression
Uncommon: Haemolytic anaemia, jaundice
What is the main side effect of Sodium Valproate?
Common: Drowsiness, Hair Loss, Stomach Pain & Diarrhoea, Weight Gain
Serious: Pancreatitis, Hepatotoxicity, Teratogenicity
What is the main side effect of Levetiracetam
?
Fatigue, Somnolence, Dizziness and headache
Extra infromation for lamotigrine
Smaller dose to delay risk of SJS allergic reaction
Extra information for Diazepam
Can’t take long term as is addictive and you build tolerance
Extra information for Sodium Valproate
Broad Inhibition of CYP enzymes means it increases serum concentration of co administered drugs
Extra information for Levetirecetam
It has no effect on cytochrome P450 so is favourable in terms of drug interaction
What is the first line treatment for absent seizures
a) women/ girls
b) boys/ men/ women
What can you add to both for adjuvant therapy
a) Ethosuximide
b) Ethosuximide or Sodium Valproate
- Lamotrigine
What is the first line treatment for focal seizures
a) women/ girls
b) boys/ men/ women
What can you add to both for adjuvant therapy
a) Carbamazepine or Levetiracetam
b) Carbamazepine or Lamotigrine
Any but sodium valproate for women of child bearing potential
What is the first line treatment for generalised tonic clonic seizures
a) women/ girls
b) boys/ men/ women
What can you add to both for adjuvant therapy
a) Lamotrigine
b) Sodium Valproate
Levetiracetam or Topirimate
What is the first line treatment for myoclonic seizures
a) women/ girls
b) boys/ men/ women
What can you add to both for adjuvant therapy
a) Levetiracetam or Topirimate
b) Sodium Valproate
Lamotrigine, Levetiracetam or Topirimate
What is the first line treatment for tonic or atonic seizures
a) women/ girls
b) boys/ men/ women
What can you add to both for adjuvant therapy
a) Sodium Valproate ( pregnancy prevention programme)
b) Sodium Valproate
Lamotrigine
How does Combined Oral Contraceptive drug affect Lamotrigine serum concentration and why?
It reduces it as it increases lamotrigine metabolism so more is cleared from blood
COC- induction of UDPGA
1) Increase dose of lamotrigine (COC can reduce lamotrigine by 50%)
2) Change contraception
How does COC affect Lamotrigine over the course of the menstrual cycle?
COC taken over four weeks:
First three weeks: active drug
Fourth week: nothing or ‘dummy’
So, fourth week - no COC affecting
liver enzymes:
Liver enzymes normalise
Lamotrigine levels increase
Epileptic episode leading to admission management
Primary options
lorazepam: 4 mg intravenously as a single dose initially, repeat dose after 5-10 minutes if required
