Seizures and Sleep

Question 1

What is the mechanism of action of benzodiazepines?

Answer 1

Hyperpolarize neurons by binding to GABA receptors resulting in a change in chloride conductance pathways - making cells resistant to depolarisation

Question 2

What is the mechanism of action of phenobarbital?

Answer 2

1. Facilitates inhibitory neurotransmission via GABA receptors
2. Inhibition of post synaptic potentials produced by glutamate
3. Inhibition of voltage gated calcium channels at excitatory nerve terminals

Also induces cytochrome P450 enzyme complex - increases its own rate of metabolism

Question 3

What is the mechanism of action of phenytoin?

Answer 3

Inactivates voltage-dependent sodium channels, preventing depolarisation of the presynaptic neuronal membrane and thus reducing release of glutamate
It is a monoaminoxidase activator - can affect plasma concentrations of other medications

Question 4

What is the mechanism of action of bromide?

Answer 4

Competes with chloride to hyperpolarize neuronal membranes, as well as enhancing GABA-activated chloride conductance