Vigabatrin is effective in infantile spasms and refractory focal seizures, but its use requires regular ophthalmological monitoring. Its mechanism and the limiting adverse effect are:

• A Irreversible inhibition of GABA transaminase; concentric visual field constriction ✓
• B SV2A binding; behavioural disturbance
• C Blockade of T-type calcium channels; retinal pigmentary changes
• D Enhanced slow inactivation of sodium channels; optic neuritis

Explanation

Vigabatrin is a structural analogue of GABA that irreversibly inhibits GABA transaminase, raising brain GABA concentrations. It is first-line for infantile spasms, particularly in tuberous sclerosis. Up to a third of patients develop bilateral concentric constriction of visual fields, which is often permanent, so it is reserved for situations where benefit outweighs this risk. SV2B binding defines levetiracetam and T-type channel blockade defines ethosuximide.

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.