The use of tranexamic acid for on-demand and prophylactic treatment of hereditary angioedema—A systematic review

Hereditary angioedema (HAE), caused by inherited deficiency of C1 esterase inhibitor (C1-INH), is characterized by recurring subcutaneous and/or submucosal edema. Although its efficacy remains controversial, tranexamic acid (TXA) is used to treat HAE in some countries. We analyzed TXA as an on-demand and prophylactic treatment in patients with HAE. Published data were systematically sourced from PubMed and Embase. All retained articles underwent grading/bias assessment using the “SIGN” grading system, and the quality of retained studies was determined following assessment of design and methodology. Of 353 studies identified, 31 were included. On-demand treatment and prophylactic treatment were assessed in five (N = 103) and 28 studies (N = 231), respectively. The majority of studies (80%) demonstrated that on-demand TXA was ineffective for skin, abdominal, or laryngeal swellings. In a single randomized controlled trial, the median time to relief of symptoms was 2 and 12 hours for icatibant and TXA, respectively (P < 0.001). For prophylaxis, while ~50% of case series, case reports, and observational studies reported beneficial effects of TXA, newer therapies, for example, icatibant and pdC1-INH, were more effective. One study found that breakthrough attacks during TXA prophylaxis lasted significantly longer compared with C1-INH (median time to resolution; 7 vs 3 hours, P = 0.016). Many studies failed to report safety data (16/31, 52%); however, pruritus, vomiting, and diarrhea were noted in some patients. There is no evidence for on-demand use of TXA in HAE and limited evidence for prophylaxis. While TXA may be more beneficial than no treatment, newer, more effective therapies should be used when available.