A-317491 is a potent, selective and non-nucleotide antagonist of P2X3 and P2X2/3 receptors, with Kis of 22, 22, 9, and 92 nM for hP2X3, rP2X3, hP2X2/3, and rP2X2/3, respectively. A-317491 is highly selective (IC50>10 μM) over other P2 receptors and other neurotransmitter receptors, ion channels, and enzymes. A-317491 reduces inflammatory and neuropathic pain by blocking P2X3 and P2X2/3 receptor-mediated calcium flux.