Etamsylate (sometimes spelled ethamsylate) is an antihemorrhagic agent which is believed to work by increasing resistance in the endothelium of capillaries and promoting platelet adhesion.

Prophylaxis and control of haemorrhages from small blood vessels, neonatal intraventricular haemorrhage,[4]: 1065  capillary bleeding of different etiology, including: menorrhagia and metrorrhagia without organic pathology, after trans-urethral resection of the prostate, hematemesis, melena, hematuria, epistaxis; secondary bleeding due to thrombocytopenia or thrombocytopathia, hypocoagulation, prevention of periventricular hemorrhages in prematurely born children.

This appears to relate to increased platelet aggregation mediated by a thromboxane A2 or prostaglandin F2a dependent mechanism.

[7] Etamsylate limits capillary bleeding through its action on hyaluronic acid and initial studies showed a reduction in intraventricular haemorrhage.

[8] Further, etamsylate has demonstrated interference with heparin, antagonizing its pro-hemorrhagic and anti-coagulant effects, without inhibiting its vasodilatory properties.