USMLE

Alteplase / tPA

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Hematology Drugs
  1. Dabigatran / Argatroban
  2. Factor Xa Inhibitors (Rivaroxaban, Apixaban)
  3. Heparin
  4. Low Molecular Weight Heparins (Enoxaparin, Fondaparinux, Dalteparin)
  5. Warfarin
  6. Aspirin
  7. GPIIb/IIIa Inhibitors (Abciximab, Tirofiban, Eptifibatide)
  8. Alteplase / tPA
  9. Iron
  10. Filgrastim
  11. Epoetin Alfa

Summary

Tissue plasminogen activator, or tPA for short, is a thrombolytic or clot busting protein that is also formulated as drug names ending in “-teplase”, like alteplase. tPA works to dissolve clots, which is used to treat medical emergencies caused by clots that block blood flow, such as a heart attack, stroke, pulmonary embolism, and even deep vein thrombosis. Clinically, tPA is often given in the setting of ischemic stroke, and in this context, it is important to administer the drug within 4 and a half hours from the start of the stroke symptoms. Beyond this time point, the dangers of giving tPA outweigh the potential benefits. One dangerous side effect to note is an increased risk for bleeding.

Key Points

  • Mechanism
    • Thrombolytic (“clot buster”)
      • Alteplase is a synthetic version of naturally occurring tissue plasminogen activator (tPA)
      • Binds to the fibrin surface of the clot to promote the conversion of plasminogen to plasmin. Plasmin is responsible for degrading fibrin as well as other clotting factors.
    • Clinical Use
      • Dissolves existing clots
        • Deep vein thrombosis (DVT)
        • Pulmonary embolism (PE)
        • Acute myocardial infarction (AMI)
        • Ischemic stroke
          • For fullest effect, must be administered within 4.5 hours from onset of symptoms (patients meeting certain criteria may be given tPA up to 4.5 hours after last known normal)
    • Side Effects and Adverse Reactions
      • Bleeding
        • Contraindicated in patients with a history of bleeding, active bleeding, uncontrolled hypertension, aneurysm, recent trauma, intracranial hemorrhage
        • Monitor for signs of bleeding like bruising, sudden drop in blood pressure, epistaxis (nosebleed)