Tranexamic Acid

Tranexamic acid is a medication that helps enhance blood clotting and is typically used to treat bleeding problems. However, it has also been shown to help prevent attacks in hereditary angioedema (HAE).

Tranexamic acid is available as oral tablets under the brand name Lysteda, which initially was sold by Xanodyne Pharmaceuticals until Ferring Pharmaceuticals obtained global marketing rights in 2010. It also is available as a direct injection into the bloodstream sold under the brand name Cyklokapron by Pfizer. Generic versions of both Lysteda and Cyklokapron also are available.

How tranexamic acid works

In HAE, too much of a substance known as bradykinin is produced, leading to attacks of swelling under the skin and on the mucous membranes of the intestines and lungs.

Bradykinin production in the body is linked to the protein plasmin, which in turn is derived from plasminogen. Tranexamic acid works by stopping the action of plasminogen, ultimately resulting in lower levels of bradykinin in the body.

Tranexamic acid in clinical trials for hereditary angioedema

Although tranexamic acid is not formally approved by the U.S. Food and Drug Administration (FDA) for the treatment of HAE, a number of guidelines support its use in preventing HAE attacks, including from the World Allergy Organization, the Canadian HAE guidelines, and the U.S. HAE Association Medical Advisory Board’s 2013 recommendations.

A retrospective observational study found that an average of 2.5 g of tranexamic acid a day taken for at least six months was able to reduce angioedema attacks by 75 percent in nearly half of the 37 patients observed, with an additional 10 patients experiencing lower levels of attacks. No adverse clotting side effects occurred, and the treatment appeared to be safe and well-tolerated by all patients.

On the other hand, a Phase 3 clinical trial (NCT00500656) found that tranexamic acid did not perform as well as Firazyr, another type of medication for HAE, in treating acute HAE attacks. Firazyr was able to relieve symptoms within two hours of taking the medication, compared to 12 hours for tranexamic acid.

Further details

Some common side effects of tranexamic acid include fatigue, headache, body aches, stomach discomfort, chills, and cold-like symptoms. More serious side effects that warrant medical attention are trouble breathing, swelling, hives, rash, itching, changes in vision, chest pain, and leg swelling and tenderness.


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