The present invention provides novel compounds of dinucleotide polyphosphates and the method of preventing or treating diseases or conditions associated with platelet aggregation. The method comprises administering systemically to a patient a pharmaceutical comprising a purinergic P2τ receptor antagonist, in an amount effective to elevate its extracellular concentration to bind to P2τ receptors and inhibit P2τ receptor-mediated platelet aggregation. Methods of systemic administration include injection by intravenous, intramuscular, intrasternal and intravitreal routes, infusion, transdermal administration, oral administration, rectal administration and intra-operative instillation.