Selective antagonist of P2Y6 nucleotide receptors; IC50 values are 37 and 98 nM at human and rat P2Y6 receptors respectively. Displays no activity at P2Y1, P2Y2, P2Y4 and P2Y11 receptors (IC50 > 10 μM). Inhibits agonist-induced cardiomyocyte contraction and UDP-induced phagocytosis.