NBQX is a potent, selective and competitive AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor antagonist. It targets both AMPA- and kainate-sensitive glutamate receptors (IC₅₀ = 0.15 and 4.8 µM, respectively). NBQX does not block the NMDA-sensitive glutamate receptor (IC₅₀ = ≥ 90 µM).