Selective, high affinity non-nucleotide P2X3 and P2X2/3 receptor antagonist (Ki values are 9, 22, 22 and 92 nM at human P2X2/3, rat P2X3, human P2X3 and rat P2X2/3, respectively); blocks recombinant human and rat P2X3 and P2X2/3 receptor-mediated calcium flux (Ki = 22 - 92 nM). Exhibits selectivity over other P2 receptors and other neurotransmitter receptors, ion channels, and enzymes (IC50 > 5 μM). Reduces mechanical allodynia and thermal hyperalgesia in the CCI in vivo models. Antinociceptive.

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