Streptokinase Dose for Myocardial Infarction
The recommended dose of streptokinase for acute myocardial infarction is 1.5 million units administered intravenously over 30-60 minutes. 1, 2
Standard Dosing Regimen
Administer 1.5 million units of streptokinase as an intravenous infusion over 30-60 minutes for patients with ST-elevation myocardial infarction (STEMI) when primary PCI cannot be performed within 120 minutes of first medical contact 1, 3
The infusion should be initiated as soon as possible, ideally within 12 hours of symptom onset, with greatest benefit occurring when given within the first 2-6 hours 1, 4
This dose achieves 60-68% TIMI 2-3 flow at 90 minutes and, when combined with aspirin, produces 42% mortality reduction 3
Mandatory Adjunctive Antiplatelet Therapy
All patients receiving streptokinase must receive concurrent antiplatelet therapy:
Aspirin: 150-325 mg loading dose (chewed or given IV if oral not possible), followed by 75-100 mg daily indefinitely 1, 3, 2, 4
Clopidogrel: 300 mg loading dose orally for patients ≤75 years (75 mg for patients >75 years), followed by 75 mg daily maintenance dose for minimum 14 days 1, 3, 2, 4
The benefits of aspirin and streptokinase are additive, with ISIS-2 trial demonstrating this synergistic effect 1
Required Anticoagulation
Anticoagulation is mandatory until revascularization or for duration of hospital stay up to 8 days:
Fondaparinux (preferred with streptokinase): 2.5 mg IV bolus followed by 2.5 mg subcutaneous once daily 1, 2, 4
- The OASIS-6 trial demonstrated fondaparinux superiority over UFH in preventing death and reinfarction, especially in patients receiving streptokinase 1
Unfractionated heparin (alternative): Weight-adjusted IV bolus followed by infusion, though less effective than fondaparinux with streptokinase 1, 2
- UFH was found to improve coronary patency after alteplase but not after streptokinase 1
Enoxaparin: For patients <75 years: 30 mg IV bolus followed by 1 mg/kg subcutaneous every 12 hours; for patients ≥75 years: no IV bolus, 0.75 mg/kg subcutaneous every 12 hours 2
Critical Contraindications
Absolute contraindication: Prior streptokinase or anistreplase administration 1, 3
Never re-administer streptokinase due to antibody formation that impairs efficacy and causes serious allergic reactions 1, 2, 4
Other absolute contraindications include any prior intracranial hemorrhage, ischemic stroke within 3-6 months, known intracranial vascular malformation or neoplasm, active bleeding, suspected aortic dissection, and severe uncontrolled hypertension 1, 4
Monitoring for Successful Reperfusion
Assess reperfusion at 60-90 minutes after initiation:
- Relief of chest pain symptoms 2, 4
- Reduction of ST-segment elevation by ≥50% 1, 2, 4
- Maintenance of hemodynamic and electrical stability 2, 4
- Presence of reperfusion arrhythmias (common and expected) 5
Post-Fibrinolysis Management
All patients must be transferred to a PCI-capable center following fibrinolysis 1, 2, 4
Rescue PCI is indicated immediately if fibrinolysis has failed (<50% ST-segment resolution at 60 minutes) 1
Routine angiography with view to revascularization is indicated after successful fibrinolysis, optimally between 3-24 hours 1, 2, 4
Emergency PCI is indicated for recurrent ischemia or evidence of reocclusion after initial successful fibrinolysis 1
Important Safety Considerations
Intracranial hemorrhage occurs in 0.9-1.0% of patients, with increased risk in those with lower weight, female sex, previous cerebrovascular disease, and hypertension on admission 1, 2, 4
Major non-cerebral bleeding occurs in 4-13% of patients treated with fibrinolytics 1, 2
Hypotension commonly occurs with streptokinase administration and should be anticipated 1, 2
Severe allergic reactions are rare but possible 1
Comparison to Alternative Agents
Fibrin-specific agents (tenecteplase, alteplase, reteplase) are generally preferred over streptokinase when available, due to better efficacy and safety profile 1, 3, 2