U-46619 is a stable analog of the endoperoxide prostaglandin H2, and a TP receptor agonist. It exhibits properties similar to thromboxane A2, causing platelet shape change and aggregation, and contraction of vascular smooth muscle. Mean EC50 values for shape change in human, rat, and rabbit platelets are 4.8, 6.0, and 7.3 nM respectively, and for aggregation are 82, 145, and 65 nM, respectively.
