Blocks and reverses platelet aggregation induced by such triggers as collagen, U-46619, and ADP (IC50 = 1.1, 2.1, and 4.1 µM, respectively); reduces tyrosine phosphorylation in stimulated platelets and inhibits recombinant human Syk and Src (IC50 = 2.8 and 27.3 µM, respectively) in vitro.