[Pharmacological aspects of a novel antiplatelet drug, E5510].

E5510 is an antiplatelet agent, recently synthesized in Japan. It inhibited human platelet aggregation ex-vivo induced by collagen, arachidonic acid, ADP, PAF, epinephrine and thrombin. In addition, it inhibited platelet adhesion and release reaction. In animal models of thrombosis, oral administration of a low dose of E5510 inhibited thrombus formation. Studies on its mode of action suggest that E5510 blocks multiple pathways of platelet activation: inhibition of arachidonic acid release, cyclooxygenase and PDE. Using healthy volunteers, inhibition of platelet aggregation was demonstrated with 1 hour after a single dose of E5510 and continued for more than 8 hours. No inhibition was observed 24 hours after administration. E5510 is currently under clinical evaluations in patients with various thrombotic diseases. This paper also describes the results of its clinical trials regarding the efficacy and safety using the patients with essential thrombocythemia.