Thromboxane A2 (TXA2) is a potent thrombogenic and vasoconstrictor eicosanoid, produced in large quantities by activated platelets. TXA2 has been implicated as a causal factor in the onset of stroke and myocardial infarction. BM 567 is a dual acting antithrombogenic agent, acting as an inhibitor of thromboxane A2 (TXA2) synthase and as an antagonist of the TP receptor, the G protein-coupled receptor mediating TXA2 activity in platelets and vascular smooth muscle. BM 567 antagonizes the vascular smooth muscle TP receptor with an IC50 value of 1.1 nM. It inhibits platelet TX synthase with an IC50 value of 12 nM.