[Antithrombotic action of benzydamine]

The non-steroidal antiinflammatory drug benzydamine (Tantum) was studied for antithrombotic properties. In vitro, rat platelet aggregation induced by adenosine diphosphate (ADP) and collagen was inhibited (IC50 about 10(-4) mol/l) and malondialdehyde formation induced by arachidonic acid in dog platelets was not influenced. The classical non-steroidal antiinflammatory drugs as indomethacin showed opposite effects. In vivo benzydamine hardly inhibited pulmonary thromboembolism induced by arachidonic acid in mice, which indicates again that the cyclooxygenase pathway is not involved. Venous thrombosis in the rat was clearly inhibited after oral administration of benzydamine (ED35 8.5 +/- 2.1 mg/kg p.o.). These results indicate that benzydamine possesses antithrombotic properties in the rat which are not based on inhibition of the cyclooxygenase system.