Alteplase, or tissue plasminogen activator (tPA), lyses clots by enhancing activation of plasminogen to plasmin. Conversely, tranexamic acid (TXA) functions by inhibiting the conversion of plasminogen to plasmin, which inhibits fibrinolysis. TXA has proven safe and effective in major bleeding with various etiologies. A 76-year-old male developed acute ischemic stroke symptoms. Systemic alteplase was administered and he showed clinical improvement. Shortly thereafter, the patient became hypotensive and lost pulses. Point-of-care ultrasound revealed cardiac tamponade. TXA was immediately given to inhibit fibrinolysis since cryoprecipitate and blood products were not immediately available. Pericardiocentesis was performed and successfully removed 200 milliliters of blood with return of pulses. Clinicians must consider TXA as a rapidly accessible antagonist of tPA’s fibrinolytic effects.