GABA potentiators

GABA potentiators

Benzodiazepines (BZD) and barbiturates are drugs that enhance GABA-receptor activation, thereby facilitating the entrance of chloride ions and thus creating a stronger inhibitory signal. This results in two effects: it raises the threshold of the action potential (and thus suppresses the focus) and it increases the inhibitory control. Diazepam and clonazepam (iv) are used to treat status epilepticus. Clobazam and clonazepam are second and third choice for the chronic control of partial and generalised seizures. The short-acting benzodiazepine midazolam

is also used as anticonvulsive and sketetal muscle relaxant treatment in status epilepticus. The most prominent side effects of the benzodiazepines are sedation and drowsiness.

Barbiturates have a similar mechanism of action as the benzodiazepines. However, in contrast to benzodiazepines they are able to open the Cl channel without the presence of GABA. This difference makes the benzodiazepines safer than the barbiturates.

Phenobarbital is an old antiepileptic and is used as alternative therapy for all types of seizures when other treatments fail. Like benzodiazepines, barbiturates are strong sedative drugs.

Vigabatrine blocks GABA transaminase resulting in decreased GABA breakdown and thus increasing GABA release into the synapse.

Tiagabine is a selective GABA reuptake inhibitor.

Valproic acid also potentiates GABA (mechanism unknown).

1

Which of the following agents has the capacity to inhibit the reuptake of GABA into neurons? 

2

Which of the following benzodiapines has an active metabolite? 

3

Which monitoring is appropriate for a patient on vigabatrin?