Pharmacokinetics of Tranexamic Acid (TXA) Delivered by Expeditious Routes in a Swine Model of Polytrauma and Hemorrhagic Shock

Hemorrhage is the leading cause of preventable death in civilian trauma centers and on the battlefield. One of the emerging treatment options for hemorrhage in austere environments is tranexamic acid (TXA). However, the landscape is not amenable to the current delivery standard. This study compared the pharmacokinetics of TXA <i>via</i> a standard 10-minute intravenous infusion (IV infusion), intravenous rapid push over 10 s (IV push), and intramuscular injection (IM) in a swine polytrauma and hemorrhagic shock model (trauma group) compared to uninjured controls (control group). Thirty swine were randomized to the trauma or control group. Following anesthesia, the trauma group experienced a simulated blast injury and 40% controlled hemorrhage. Subjects in both groups were then randomized to receive 1 g/10 mL TXA <i>via</i> IV infusion, IV push, or IM. Animals were monitored for four hours with serial blood sampling. Serum TXA concentrations were measured by liquid chromatography with tandem mass spectrometry (LC-MS/MS) and analyzed. The time to maximum TXA concentration (T_max) was not affected by trauma in IV infusion or IV push, but was affected in the IM administration with T_max significantly slower than the control group (<i>p</i> = 0.016). The minimum effective serum concentration of TXA (C_eff, 10 µg/mL) was reached in less than one minute with IV infusion and instantaneously with IV push. Despite lower bioavailability, the time to reach C_eff (T_eff) was achieved <i>via</i> IM administration in less than 10 min for both groups (6.4 min trauma vs. 2.1 min control). In austere prehospital environments, an alternative to intravenous infusion of a life-saving medication is desired. Administration of TXA <i>via</i> all three methods reached the level needed to cause substantial inhibition of fibrinolysis within 10 min. The IV push method showed similar pharmacokinetics to IV infusion of TXA but can be delivered quickly without sacrificing an access site for 10 min.