Mode of action of mood stabilisers

Question 1

Carbamazepine

Answer 1

• prolongs sodium channel linactivation
• calcium channel inactivation is also prolonged
• glutamate neurotransmission is reduced and brain catecholamine activity is increased
• inhinits peripheral benzodiazepine receptors and reduces limbic kindling
• interfers with glial cell steroidogenesis

Question 2

Gabapentin

Answer 2

• GABA analogue
• binds to the alpha-2-delta subunit of the voltage-dependent calcium channel in the CNS
• increases GABA availability in the brain
• crosses the BBB
• High affinity for the GABA-A complex
• no benzo-like action noted

Question 3

Lamotrigine

Answer 3

• blocks voltage sensitive sodium channels leading to modulation of glutamate and aspartate release
• has some effect on calcium channels
• some inhibition of serotonin reuptake and weak inhibition of 5-HT3 receptors
• NMDA antagonist

Question 4

Leveteracetam

Answer 4

-indirectly enhances GABA system

Question 5

Pregabalin

Answer 5

• GABA analogue
• more potent than gabapentin
• high therapeutic index, fewer dose-related side effects

Question 6

Tiagabine

Answer 6

• potent selective reuptake inhibitor of GABA

- also mild antihistaminic effects

Question 7

Topiramate

Answer 7

• fructose derivative
• selective inhibitor of glutamate AMPA receptors
• blocks sodium receptors
• indirect GABAergic activity by potentiating the action of GABAA receptor

Question 8

Valproic acid

Answer 8

• speculated to act via increased GABA release
• decreased GABA metabolism
• increased neuronal responsiveness to GABA and increased GABA receptor density
• inhibition of phosphokinase c
• functional dopamine antagonism
• NMDA antagonism

Question 9

Vigabatrin

Answer 9

• expands as Vi-GAGA-TR-transaminase-In-inhibitor

- GABA transaminase inhibitor