What is the mechanism of action of vigabatrin?

Vigabatrin's mechanism of action primarily involves the inhibition of GABA transaminase, which is an enzyme responsible for the breakdown of GABA (gamma-aminobutyric acid), the principal inhibitory neurotransmitter in the central nervous system. By inhibiting this enzyme, vigabatrin leads to an increase in the levels of GABA in the synaptic cleft. This elevated concentration enhances the inhibitory action of GABA, resulting in increased gamma-aminobutyric activity, which can help control seizures in patients with epilepsy.

This mechanism underscores its clinical utility, particularly in patients with refractory complex partial seizures and infantile spasms. The effectiveness of vigabatrin in seizure management can be attributed to this specific action on GABA metabolism rather than simply increasing GABA receptor activity or affecting GABA reuptake processes. Other approaches, such as being an agonist at GABA-A receptors, are not applicable here, as vigabatrin does not directly bind to these receptors. Instead, its role as a GABA transaminase inhibitor is what differentiates it in the therapeutic landscape.