SCH79797 dihydrochloride is a highly potent, selective nonpeptide protease activated receptor 1 ( PAR1 ) antagonist. SCH79797 dihydrochloride inhibits binding of a high-affinity thrombin receptor-activating peptide to PAR1 with an IC 50 of 70 nM and a K i of 35 nM. SCH79797 dihydrochloride inhibits thrombin-induced platelet aggregation with an IC 50 of 3 μM. SCH79797 dihydrochloride has antiproliferative and pro-apoptotic effects, and limits myocardial ischemia/reperfusion injury in rat hearts. SCH79797 dihydrochloride also potently prevents PAR1 activation in vascular smooth muscle cells, endothelial cells, and astrocytes .