Anticonvulsant

Question 1

Drugs

Answer 1

Lamotrigine
Sodium valproate
Diazepam
Levetiracetam

Question 2

Lamotrigine action

Answer 2

Blocks voltage gated Na+ channels preventing Na+ influx. Prevents depolarisation of glutamatergic neurones and reduces glutamate excitotoxicity

Question 3

Lamotrigine target

Answer 3

Voltage gated sodium channels

Question 4

Lamotrigine side effects

Answer 4

Common: Rash, drowsiness

Less common but serious:
Steven-Johnson’s syndrome, suicidal thoughts

Question 5

Lamotrigine other

Answer 5

Introducing lamotrigine gradually is one of the keys to reducing the frequency and severity of allergic skin reactions.

In 2020 – Lamotrigine was the 94th most commonly prescribed drug in West London area

Question 6

Sodium valproate action

Answer 6

Inhibition of GABA transaminase prevents the breakdown of GABA. This increases GABA concentrations directly in the synapse presynaptically and 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.

Question 7

Sodium valproate target

Answer 7

GABA transaminase

Question 8

Sodium valproate side effects

Answer 8

Common: Stomach pain and diarrhoea, drowsiness, weight gain, hair loss
Serious:
hepatotoxicity, teratogenicity, pancreatitis

Question 9

Sodium valproate other

Answer 9

Broad CYP enzyme inhibitor - increases serum concentration of many co-administered drugs

In 2020 – Sodium valproate was the 78th most commonly prescribed drug in West London area

Question 10

Diazepam action

Answer 10

Increases choride ion influx in response to GABA binding at the GABA A receptor. Increased chloride ion influx associated with hyperpolarisation of excitatory neurones.

Question 11

Diazepam target

Answer 11

Benzodiazepine site on the GABA A receptor

Question 12

Diazepam side effects

Answer 12

Common: Drowsiness, respiratory depression (if i.v. or at high dose)
Uncommon but serious:
Haemolytic anaemia, jaundice

Question 13

Diazepam other

Answer 13

Main reason that diazepam is not used for long term suppression of seizures is due to the development of tolerance.

Diazepam is a Schedule 4 controlled drug - addiction prone individuals more likely to become dependent on diazepam.

In 2020 – Diazepam was the 61st most commonly prescribed drug in West London area

Question 14

Levetiracetam action

Answer 14

Inhibition of the synaptic vesicle protein SV2A. It inhibits this protein and prevents vesicle exocytosis. A reduction in glutamate secretion is reduces glutamate excitotoxicity

Question 15

Levetiracetam target

Answer 15

Synaptic vesicle protein SV2A

Question 16

Levetiracetam side effect

Answer 16

Common:

dizziness, somnolence, fatigue and headache

Question 17

Levetiracetam other

Answer 17

The metabolism of levetiracetam has no effect on the cytochrome P450 enzyme system so it is favorable in terms of no drug–drug interactions.

In 2020 – Levetiracetam was the 74th most commonly prescribed drug in West London area