Aminocaproic Acid

Aminocaproic acid, also known as 6-aminocaproic acid or epsilon-aminocaproic acid, is an antifibrinolytic used to treat hemophilia, and to control bleeding during surgery. Antifibrinolytics prevent the breakdown of blood clots, a process known as fibrinolysis, and help in controlling excess blood loss.

Aminocaproic acid was originally commercially available as Amicar from Xanodyne Pharmaceuticals (now closed) and was granted U.S. Food and Drug Administration (FDA) approval in 1998 for use as an antifibrinolytic. A generic equivalent to Amicar, produced by Vitruvias Therapeutics and Sunny Pharmtech, was granted approval by the FDA in 2018.

How Aminocaproic acid works

Hemostasis is an important physiological process that regulates the formation of blood clots at a site of injury without disturbing the flow of blood in other parts of the body. The formation of blood clots (coagulation) and dissolution of clots (fibrinolysis) are tightly controlled processes that involve multiple proteins, including clotting factors plasminogen, plasminogen activators, plasmin, thrombin, and fibrin.

Aminocaproic acid works in either of two ways:

  1. By inhibiting plasminogen activators that aid the formation of plasmin from plasminogen. Plasmin helps dissolve fibrin, which is an integral component of blood clots. With the absence of active plasmin upon aminocaproic acid treatment, the clot is retained and blood loss is controlled.
  2. By inhibiting the binding of plasminogen to fibrin. When not active, plasminogen remains bound to fibrin and must be converted to plasmin before the clot can be dissolved. Aminocaproic acid binds to plasminogen and prevents its binding to fibrin, thus preventing fibrinolysis.

Aminocaproic acid in clinical trials

Aminocaproic acid has not been tested specifically in patients with hemophilia, but its effectiveness in controlling blood clotting has been investigated in other clinical trials. For example, a Phase 4 clinical trial (NCT02030821) compared the effectiveness of aminocaproic acid and another antifibrinolytic, tranexamic acid (TXA), in decreasing blood loss during total knee and hip replacement surgery. The results of the trial, completed in 2017, showed that both aminocaproic acid and TXA were effective in reducing the need for post-operative blood transfusion.

A Phase 2 trial (NCT02074436) to assess the effectiveness of aminocaproic acid treatment in preventing bleeding in patients with blood cancer is currently underway and is expected to be completed in May 2019.

Other information

The dosage of aminocaproic acid needed depends on the extent of bleeding. It is usually taken once every hour for about six to eight hours until the bleeding stops. Care should be taken to follow the exact dosage instructions as prescribed by the clinician.


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