Tranexamic Acid for Acute Upper Respiratory Tract Infection-Associated Sore Throat Pain: A Randomized Controlled Trial.

Background: Tranexamic acid (TXA) is sometimes used to relieve sore throat discomfort from acute upper-respiratory tract infection (URTI), but its clinical effect has not been demonstrated in robust randomized controlled trials. Methods: The tranexamic acid for URTI study is a randomized double-blinded clinical trial that was conducted between November 2023 and March 2025. Patients with URTI and a sore throat (18-65 years old) were randomized to receive either 1 g placebo (lactose) or 1 g preparation of 50% TXA. Randomization was stratified according to age (< 45 vs. ≥ 45 years) and baseline sore throat visual analog scale (VAS) score (< 50 vs. ≥ 50). Change in the proportion of patients with sore throat score more than a moderate level within a 2-h period after taking TXA was the primary outcome. We also examined the difference in sore throat VAS scale score between before and 2 h after TXA was taken. Data were analyzed using analysis of covariance, controlling for stratification factors. Results: We analyzed the 17 participants assigned to each group (total = 34). The groups were not significantly different in the proportion of patients whose sore throat had a moderate or greater impact on their day-to-day life (TXA 41.2% vs. placebo 47.1%; Conclusion: TXA was not significantly better than a placebo at relieving acute URTI-associated sore throat. Trial Registration: UMIN000056394.