The effect of tranexamic acid on the fibrinolytic activity of vein walls.

16 patients were treated with the fibrinolytic inhibitor tranexamic acid in an initial i.v. dose of 1 g followed by an oral dose of 4 g a day for one week and 3 g a day for two weeks. Biopsy specimens of superficial veins were obtained before and on the last day of treatment and examined histochemically for their fibrinolytic activity. Tranexamic acid did not suppress the fibrinolytic activity in the vessel walls, which is the most important link in the fibrinolytic defence system against thrombosis.