Dixon AL, McCully BL, Rick EA, et al. - In patients with moderate to severe TBI, researchers here examined if and how tranexamic acid (TXA) affects markers of coagulation and fibrinolysis. They retrieved data from a placebo-controlled clinical trial in which prehospital randomization was performed with patients 15 years or older with TBI (Glasgow Coma Scale, 3–12) and systolic blood pressure of ≥ 90 mm Hg to receive placebo bolus/placebo infusion (placebo), 1 g of TXA bolus/1 g of TXA infusion (bolus maintenance), or 2 g of TXA bolus/placebo infusion (bolus only). A total of 966 patients received the study drug; among these, 700 had laboratory tests drawn at admission and 6 hours later. Findings revealed D-dimer and plasmin-antiplasmin levels inferred a lower degree of fibrinolysis after prehospital administration of TXA vs placebo in this large prehospital trial of patients with TBI; no difference was seen in fibrinolysis between the two TXA dosing regimens and placebo according to thromboelastography retrieved on admission and 6 hours later.