止血劑 (haemostatic) Antiplasmin (antifibrinolytic) agent. Used in haemorrhage caused by administration of plasminogen activators (streptokinase, urokinase), obstetric complications, and in hyperplasminaemic states.
藥理
Tranexamic acid is a competitive inhibitor of plasminogen activation, and at much higher concentrations, a noncompetitive inhibitor of plasmin, i.e., actions similar to aminocaproic acid.
藥動學
The plasma protein binding of tranexamic acid is about 3% at therapeutic plasma levels and seems to be fully accounted for by its binding to plasminogen. Tranexamic acid does not bind to serum albumin. The initial volume of distribution is about 9 to 12 liters. Urinary excretion is the main route of elimination via glomerular filtration. Overall renal clearance is equal to overall plasma clearance (110 to 116 mL/min), and more than 95% of the dose is excreted in the urine as unchanged drug. An antifibrinolytic concentration of tranexamic acid remains in different tissues for about 17 hours, and in the serum, up to seven or eight hours.
禁忌症
Active intravascular clotting process, acquired defective color vision, subarachnoid hemorrhage, hypersensitivity to tranexamic acid.
懷孕分類
B
哺乳分類
Tranexamic acid should be used during lactation only if clearly needed.