anticonvulsants 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 is the drug target of lamotrigine?
Voltage gated Na+ channels
What are the main common side effects of lamotrigine?
- Rash
- Drowsiness
What are the less common but serious side effects of lamotrigine?
- Steven-Johnson’s syndrome
- Suicidal thoughts
Why is lamotrigine introduced gradually?
Introduction of lamotrigine is gradual to reduce frequency and severity of allergic skin reactions
What is the primary mechanism of action of sodium valproate?
- Inhibition of GABA transaminase prevents breakdown of GABA
- Increases GABA conc directly in synapse presynaptically
- Also indirectly prolongs GABA in synapse since extraneuronal GABA metabolism is slowed which also slows GABA removal from synapse
What is the drug target of sodium valproate?
GABA transaminase
What are the main common side effects of sodium valproate?
- Diarrhoea
- Drowsiness
- Weight gain
- Hair loss
What are the main serious side effects of sodium valproate?
- Hepatotoxicity
- Teratogenicity
- Pancreatitis
What else does sodium valproate act as?
It’s a broad CYP enzyme inhibitor: increases serum concentration of many co-administered drugs
What is the primary mechanism of action of diazepam?
- Increases Cl- influx in response to GABA binding at GABA A receptor
- This hyperpolarises the excitatory neurones
What is the drug target of diazepam?
Benzodiazepine site on GABA A receptor
What are the main common side effects of diazepam?
- Drowsiness
- Respiratory depression (if IV or at high dose)
What are uncommon but serious side effects of diazepam?
- Haemolytic anaemia
- Jaundice
Why is diazepam not used long term for suppression of seizures?
Tolerance develops, and it is also an addictive drug
What is the primary mechanism of action of levetiracetam?
- Inhibition of synaptic vesicle protein SV2A
- This prevents vesicle exocytosis
- Reduces glutamate secretion and therefore glutamate excitotoxicity
What is the drug target of levetiracetam?
Synaptic vesicle protein SV2A
What are the main side effects of levetiracetam?
- Somnolence (drowsiness)
- Dizziness
- Fatigue
- Headache
What makes levetiracetam favourable in terms of drug-drug interactions?
Levetiracetam has no effect on cytochrome P459 enzyme system
What is the first line treatment for absence seizures from boys/men/women with no child-bearing potential?
Ethosuximide or sodium valproate
What is the first line treatment for absence seizures from girls/women with child bearing potential?
Ethosuximide
What is the adjunctive treatment for absence seizures from boys/men/women with no child-bearing potential?
Combine 2 of ethosuximide, sodium valproate or lamotrigine
What is the adjunctive line treatment for absence seizures from girls and women with child-bearing potential?
Combine 2 of ethosuximide and lamotrigine
What is the first line treatment for focal seizures from boys/men/women with no child-bearing potential?
Carbamazepine or lamotrigine
What is the first line treatment for focal seizures from girls/women with child-bearing potential?
Carbamazepine or levetiracetam
What is the adjunctive treatment for focal seizures from boys/men/women with no child-bearing potential?
Any
What is the adjunctive treatment for focal seizures from girls/women with child-bearing potential?
Any (not sodium valproate)
What is the first line treatment for general tonic-clonic seizures from boys/men/women with no child-bearing potential?
Sodium valproate
What is the first line treatment for general tonic-clonic seizures from boys/men/women with no child-bearing potential?
Lamotrigine (or carbamazepine)
What is the adjunctive treatment for general tonic-clonic seizures from boys/men/women with no child-bearing potential?
Combine 2 of sodium valproate, levetiracetam or topiramate
What is the adjunctive line treatment for general tonic-clonic seizures from girls/women with child-bearing potential?
Combine levetiracetam and topiramate
What is the first line treatment for myoclonic seizures from boys/men/women with no child-bearing potential?
Sodium valproate
What is the first line treatment for myoclonic seizures from girls/women with child-bearing potential?
Levetiracetam or topiramate
What is the adjunctive treatment for myoclonic seizures from boys/men/women with no child-bearing potential?
Clobazam, lamotrigine, levetiracetam or topirimate
What is the first line treatment for myoclonic seizures from girls/women with child-bearing potential?
Levetiracetam or topiramate
What is the first line treatment for tonic or atonic seizures from boys/men/women with no child-bearing potential?
Sodium valproate
What is the first line treatment for tonic or atonic seizures from girls/women with child-bearing potential?
Sodium valproate (pregnancy prevention programme)
What is the adjunctive treatment for tonic or atonic seizures from boys/men/women with no child-bearing potential?
Lamotrigine
What is the adjunctive treatment for tonic or atonic seizures from girls/women with child-bearing potential?
Lamotrigine
