Tranexamic Acid for Hereditary Angioedema

Introduction to Tranexamic Acid

Tranexamic acid (TXA) is given for hereditary angioedema (HAE) primarily as long-term prophylaxis to reduce attack frequency, particularly when first-line C1-inhibitor therapies are unavailable, and is especially preferred in children, pregnancy (after first trimester), and resource-limited settings due to its favorable safety profile 1, 2

TXA should be considered as long-term prophylaxis when first-line C1-inhibitor therapies are unavailable, either alone or in combination with attenuated androgens 1
The recommended dosing is 30-50 mg/kg/day in 2-3 divided doses, with a maximum of 3-4 g daily 3, 4
TXA may be considered for short-term prophylaxis before procedures, but its efficacy is questionable for this indication 5, 2
When used for short-term prophylaxis, doses of 30-50 mg/kg or maximum 3-4.5 g daily in 2-3 divided doses from 5 days before until 2 days after the procedure have been suggested 1
Androgens appear more effective than TXA for short-term prophylaxis 6

TXA should be the preferred drug for long-term prophylaxis in children when first-line agents are unavailable 2
Pediatric dosing is 15-25 mg/kg twice or three times daily (maximum), adjusted for gastrointestinal tolerability and efficacy 1, 7
TXA can be considered for HAE prophylaxis during pregnancy, preferably after the first trimester, when C1-inhibitor is unavailable 2, 8

TXA is well-tolerated, inexpensive, and has a very high safety profile compared to attenuated androgens 3, 4
Main side effects are digestive in nature (nausea, diarrhea, gastrointestinal discomfort) 4
Recent thrombosis, atrial fibrillation, or known thrombophilia are relative contraindications 7
TXA is not FDA-approved specifically for HAE but is approved as an antifibrinolytic agent 4
Efficacy is variable—while some patients achieve excellent control, approximately 27% in one study showed minimal reduction in attacks 1, 3
TXA is considered a second-line or alternative therapy when C1-inhibitor replacement, icatibant, or ecallantide are unavailable 1, 3

The American Academy of Allergy, Asthma, and Immunology suggests that tranexamic acid (TXA) appears less effective than attenuated androgens but has a significantly better safety profile for hereditary angioedema (HAE) prophylaxis, with 46% of patients achieving a 75% reduction in attack frequency 9
The World Allergy Organization notes that TXA is not effective as monotherapy for acute HAE attacks, and standard angioedema treatments including epinephrine, corticosteroids, and antihistamines are ineffective for HAE because the mechanism involves bradykinin, not histamine 9

The European Academy of Allergy and Clinical Immunology recommends that TXA can be considered for HAE prophylaxis during pregnancy, preferably after the first trimester, when C1-inhibitor is unavailable, due to its superior safety profile compared to androgens 9