A 58-year-old man presents to the emergency department with acute anterior wall myocardial infarction (STEMI) of 2 hours duration. He has no contraindications to fibrinolytic therapy and is in a non-PCI-capable hospital. Which is the drug of choice for immediate reperfusion therapy?
A. Aspirin
B. Metoprolol
C. Alteplase
D. Clopidogrel
Explanation
Fibrinolytic Therapy in STEMI
Key Point
Alteplase (tissue plasminogen activator, tPA) is the preferred fibrinolytic agent for acute STEMI in non-PCI-capable hospitals when primary PCI cannot be performed within 120 minutes of first medical contact.
Mechanism of Action
Alteplase is a recombinant tissue plasminogen activator that:
Directly activates plasminogen to plasmin
Exhibits fibrin-selectivity (preferentially binds to fibrin in thrombi)
Achieves TIMI 3 flow in ~50–60% of patients when given within 12 hours of symptom onset
Dosing in Acute MI
Bolus: 15 mg IV over 1–2 minutes
Infusion: 0.75 mg/kg over 30 minutes (max 50 mg), then 0.5 mg/kg over 60 minutes (max 35 mg)
Total dose should not exceed 100 mg
Comparison of Fibrinolytic Agents
Table
Agent
Fibrin-Selectivity
TIMI 3 Flow
Bleeding Risk
Reperfusion Arrhythmia
Alteplase (tPA)
High
50–60%
Moderate
Common
Reteplase (rPA)
High
60%
Moderate
Common
Tenecteplase (TNK)
Very high
65%
Lower
Common
Streptokinase
Low
40–50%
Higher
Common
High-YieldNEET PG
Alteplase is preferred in anterior MI and in patients <75 years with symptom onset <3 hours because it achieves superior patency rates compared to streptokinase.
Clinical Pearl
Reperfusion arrhythmias (accelerated idioventricular rhythm, ventricular tachycardia) indicate successful coronary recanalization and are a favorable prognostic sign.
Contraindications to Fibrinolysis
Active internal bleeding
Recent intracranial hemorrhage or stroke (within 3 months)
Intracranial neoplasm or AVM
Severe uncontrolled hypertension (SBP >180 mmHg, DBP >110 mmHg)
Recent major surgery or trauma (within 2–4 weeks)
Warning
Do NOT confuse fibrinolytic choice with antiplatelet/anticoagulant adjuncts. Aspirin and clopidogrel are given alongside fibrinolysis, not instead of it.
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