Praxis Medical Insights

Est. 2024 • Clinical Guidelines Distilled

Made possible by volunteer editors from the University of Calgary & University of Alberta

Last Updated: 9/27/2025

Thrombolytic Treatment of STEMI

Primary Thrombolytic Agents

  • The European Society of Cardiology recommends using a fibrin-specific thrombolytic agent, such as tenecteplase, alteplase, or reteplase, as the primary thrombolytic medication for STEMI when fibrinolysis is the chosen reperfusion strategy, with a Class I, Level B recommendation 1, 2, 3
  • Alteplase should be administered as an infusion over approximately 90 minutes 1
  • For patients ≥75 years of age, the European Society of Cardiology suggests considering half-dose tenecteplase to reduce bleeding risk while maintaining efficacy 4

Essential Adjunctive Antiplatelet Therapy

  • The European Society of Cardiology recommends administering aspirin as soon as possible, with a Class I, Level B recommendation 1, 3, 5
  • The American College of Cardiology recommends clopidogrel in addition to aspirin, with a Class I, Level A recommendation, and a loading dose of 300 mg is reasonable for patients <75 years 1, 2, 3, 6
  • Clopidogrel should be continued for at least 14 days, with consideration for up to 12 months 6, 4

Mandatory Anticoagulation Co-Therapy

  • The European Society of Cardiology recommends anticoagulation in all patients receiving thrombolytics until revascularization or for hospital duration up to 8 days, with enoxaparin as the preferred option over unfractionated heparin (UFH) 1, 2, 3, 7, 5, 8
  • Unfractionated heparin (UFH) is recommended as a Class I, Level B option, with a weight-adjusted IV bolus followed by infusion 1, 3, 5
  • Fondaparinux is recommended as a Class IIa, Level B option, specifically for patients treated with streptokinase (non-fibrin-specific agent) 4

Timing and Administration

  • The European Society of Cardiology recommends initiating fibrinolytic therapy as soon as possible after STEMI diagnosis, preferably in the pre-hospital setting, with a Class I, Level A recommendation, and the greatest mortality benefit occurs when treatment is given within 6 hours of symptom onset 1, 2, 3, 4
  • Efficacy decreases substantially after 3 hours, making primary PCI increasingly preferable as time from symptom onset increases 4

Important Clinical Pitfalls

  • The American College of Cardiology recommends avoiding fondaparinux as sole anticoagulation during PCI, as it increases catheter thrombosis risk and requires additional UFH or bivalirudin 6, 8

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