What are the thrombolytic therapy options for acute myocardial infarction (AMI)?

Updated: Aug 04, 2021
  • Author: Wanda L Rivera-Bou, MD, FAAEM, FACEP; Chief Editor: Erik D Schraga, MD  more...
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Aspirin inhibits platelets; the recommended dose is 162-325 mg of chewable aspirin.

Clopidogrel also inhibits platelets. For patients aged 75 years or younger, administer an oral loading dose of 300 mg. The COMMIT-CCS-2 and CLARITY-TIMI 28 trials provided evidence for benefit of adding clopidogrel to aspirin in patients undergoing fibrinolytic therapy. [25, 26] In patients older than 75 years, no loading dose is required; administer 75 mg orally. [16]

Heparin (unfractionated heparin [UFH] or low-molecular-weight heparin [LMWH]) inhibits thrombin. For UFH, the recommended dose is an intravenous (IV) bolus of 60 U/kg (maximum, 4000 U) followed by an initial infusion of 12 U/kg/hr (maximum, 1000 U/hr) adjusted to maintain the activated partial thromboplastin time (aPTT) at 1.5-2 times the control value.

LMWH (eg, enoxaparin) is emerging as an alternative to UFH. Enoxaparin may be administered to patients younger than 75 years; the recommendation is a 30 mg IV bolus followed by 1 mg/kg subcutaneously every 12 hours. For patients aged 75 years or older, the IV bolus is eliminated and the subcutaneous dose reduced to 0.75 mg/kg every 12 hours. Regardless of age, if the creatinine clearance is less than 30 mL/min, the subcutaneous dose is 1 mg/kg every 24 hours. [16] Enoxaparin appeared superior to UFH in the EXTRACT-TIMI 25 trial. [27]

Fondaparinux should not be given as the sole anticoagulant to patients referred for PCI and is contraindicated for patients with a creatinine clearance of less than 30 mL/min.

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