Anticonvulsants Core Drugs Flashcards
What is the primary mechanism of action of lamotrigine?
- Blocks voltage gated Na+ channels preventing Na+ influx
2. Prevents depolarisation of glutamatergic neurones and reduces glutamate excitotoxicity
What is the drug target for lamotrigine?
Voltage gated Na+ channels
What are the common side effects of lamotrigine?
- Rash
- drowsiness
What are the less common but serious side effects of lamotrigine?
- Steven-Johnson’s syndrome
- suicidal thoughts
How do you reduce the frequency and severity of allergic skin reactions?
Introducing lamotrigine gradually
How commonly were these drugs prescribed in 2020 in West London?
- Lamotrigine: 94th
- Sodium valproate: 78th
- Diazepam: 61st
- Levetiracetam: 74th
What is the primary mechanism of. action for sodium valproate?
- Inhibition of GABA transaminase prevents the breakdown of GABA
- Increases GABA concentrations directly in the synapse presynaptically
- 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 common side effects of sodium valproate?
- Stomach pain
- diarrhoea
- drowsiness
- weight gain
- hair loss
What are the serious side effects of sodium valproate?
- hepatotoxicity
- teratogenicity
- pancreatitis
What does a broad CYP enzyme inhibitor cause?
increases serum concentration of many co-administered drugs
What is the primary mechanism of action for diazepam?
- 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 for diazepam?
Benzodiazepine site on the GABA A receptor
What are the common side effects of diazepam?
- Drowsiness
- Respiratory depression (if i.v. or at high dose)
What are the uncommon but serious side effects of diazepam?
- Haemolytic anaemia
2. jaundice
What. is the main reason that diazepam is not sued for long term?
not used for long term suppression of seizures is due to the development of tolerance
What type of schedule is diazepam and what does this mean?
Diazepam is a Schedule 4 controlled drug - addiction prone individuals more likely to become dependent on diazepam
What is the primary mechanism of action of levetiracetam?
- Inhibition of the synaptic vesicle protein SV2A
- 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 the common side effects of levetiracetam?
- dizziness
- somnolence
- fatigue
- headache
Does levetiracetam have drug interactions?
The metabolism of levetiracetam has no effect on the cytochrome P450 enzyme system so it is favorable in terms of no drug–drug interactions
