Question

Which of the following is not a GABA derivative:

• A. Pregabalin
• B. Vigabatrin
• C. Gabapentin
• D. Rufinamide

Answer 1

The Correct Option is D

The correct option is (D): Rufinamide.

Answer 2

Several antiepileptic drugs are structurally derived from gamma-aminobutyric acid (GABA), designed either to mimic GABA or to influence its metabolism, while others belong to unrelated chemical classes. Checking each drug against this:

1. Pregabalin: Pregabalin is a structural analogue of GABA, designed to bind the alpha-2-delta subunit of voltage-gated calcium channels; it is chemically classed as a GABA derivative/analogue.
2. Vigabatrin: Vigabatrin is also a GABA analogue; it works by irreversibly inhibiting GABA transaminase, the enzyme that breaks down GABA, thereby raising GABA levels in the brain. It is structurally derived from GABA.
3. Gabapentin: As its name suggests, gabapentin was designed as a GABA analogue, structurally related to GABA, that also acts on calcium channels rather than GABA receptors directly.
4. Rufinamide: Rufinamide is chemically a triazole derivative, unrelated in structure to GABA. Its antiepileptic action comes from prolonging the inactive state of voltage-gated sodium channels, a completely different mechanism and chemical origin from the GABA-related drugs.

Three of the four drugs are chemically built on the GABA structure, while rufinamide belongs to an entirely different chemical class.

Therefore, the correct answer is Rufinamide.