Etamsylate

Etamsylate is a haemostatic agent.  It acts on the first step of hemostasis by improving platelet adhesiveness and restoring capillary resistance. Recent studies showed that Ethamsylate promotes P-selectin-dependent, platelet adhesive mechanisms.  Haemostatic action is due to activation of thromboplastin formation on damaged sites of small blood vessels and decrease of Prostacyclin l2 synthesis. 

The exact mechanism of action is unknown.  It has been shown to facilitate the aggregation of platelets mediated by a thromboxane A2 or prostaglandin F2a-dependent mechanism.  

Researchers measured the expression of P-selectin in the membrane of SV40-transformed aortic rat endothelial cells. There was a significant increase in the percentage of platelets expressing P-selectin even at the lowest concentration (1 uM), with maximal enhancement at 10 uM (Alvarez-Guerra M et al, 2002).

Etamsylate inhibited prostaglandin biosynthesis in microsomes of pregnant human myometrium with IC50 of 0.5mM.  It is active against hydroxyl radicals.  It potentiates human platelet aggregation and ATP release induced by arachidonic acid, thromboxane A2, collagen, and calcium inophore A23187 (Garay, 2006). 

Alvarez-Guerra M et al (2002) The hemostatic agent Ethamsylate enhances P-selectin membrane expression in human platelets and cultured endothelial cells. Thromb. Res. 107(6):329-335 PMID 12565720

Garay RP, Chiavaroli C, and Hannaert P (2006) Therapeutic efficacy and mechanism of action of Ethamsylate, a long-standing hemostatic agent. Am. J. Ther. 13(3):236-247 PMID 16772766