The anticonvulsant action of vigabatrin is best explained by:

• A Reversible competitive inhibition of GABA transaminase
• B Positive allosteric modulation of the synaptic GABA-B receptor
• C Blockade of the GAT-1 neuronal GABA transporter
• D Irreversible suicide inhibition of GABA transaminase, raising brain GABA levels ✓

Explanation

Vigabatrin is a structural analogue of GABA that irreversibly inactivates GABA transaminase (GABA-T), the enzyme degrading GABA, thereby increasing CNS GABA concentrations. Because inhibition is irreversible, effect outlasts the drug's plasma half-life. Tiagabine, not vigabatrin, blocks the GAT-1 transporter, and baclofen is the GABA-D agonist. Its use is limited by irreversible concentric visual field constriction.

Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.