What is the recommended dosage of streptokinase (Streptokinase) injection for the treatment of ST-elevation myocardial infarction (STEMI)?

Streptokinase Dosage for ST-Elevation Myocardial Infarction

For ST-elevation myocardial infarction (STEMI), streptokinase should be administered as a 1.5 million unit intravenous infusion over 30-60 minutes. 1

Dosing Protocol

The recommended dosing protocol for streptokinase in STEMI is:

• Dose: 1.5 million units
• Administration: Intravenous infusion
• Duration: 30-60 minutes 1

Adjunctive Therapy

Streptokinase should always be administered with:

1. Antiplatelet therapy:

   • Aspirin: 150-325 mg oral loading dose (chewable, non-enteric coated) or 250-500 mg IV if oral ingestion not possible 1
   • Clopidogrel: 300 mg loading dose for patients ≤75 years; 75 mg for patients >75 years 1

2. Anticoagulant therapy (for minimum of 48 hours, preferably for duration of hospitalization, up to 8 days):

   • Unfractionated heparin (UFH): Weight-based IV bolus of 60 U/kg (maximum 4000 U) followed by infusion of 12 U/kg/h (maximum 1000 U/h) initially, adjusted to maintain aPTT at 1.5-2.0 times control for 48 hours or until revascularization 1
   • OR Enoxaparin: For age <75 years - 30 mg IV bolus, followed in 15 minutes by 1 mg/kg subcutaneously every 12 hours (maximum 100 mg for first 2 doses); For age ≥75 years - no bolus, 0.75 mg/kg subcutaneously every 12 hours (maximum 75 mg for first 2 doses) 1

Contraindications

Absolute Contraindications:

• Any prior intracranial hemorrhage
• Known structural cerebral vascular lesion
• Known malignant intracranial neoplasm
• Ischemic stroke within 3 months
• Suspected aortic dissection
• Active bleeding or bleeding diathesis
• Significant closed-head or facial trauma within 3 months
• Prior treatment with streptokinase within previous 6 months (specific to streptokinase) 1

Relative Contraindications:

• History of chronic, severe, poorly controlled hypertension
• Significant hypertension on presentation (SBP >180 mmHg or DBP >110 mmHg)
• History of prior ischemic stroke >3 months
• Traumatic or prolonged CPR (>10 minutes)
• Major surgery within 3 weeks
• Recent internal bleeding (within 2-4 weeks)
• Noncompressible vascular punctures
• Pregnancy
• Active peptic ulcer
• Current oral anticoagulant therapy 1

Monitoring and Complications

1. Monitor for reperfusion:

   • Resolution of chest pain
   • ST-segment resolution (>50% reduction)
   • Early peaking of cardiac enzymes 2

2. Common complications:

   • Hypotension: Occurs in approximately 40% of patients receiving accelerated regimens, typically within 9±5 minutes after starting infusion. Usually resolves within 16±6 minutes without specific therapy 3
   • Reperfusion arrhythmias: Common and may include ventricular tachycardia or ventricular fibrillation 4
   • Bleeding: Monitor for any signs of bleeding, particularly intracranial hemorrhage

Evidence for Accelerated Administration

Recent evidence suggests that accelerated administration of streptokinase (over 30 minutes instead of 60 minutes) may be associated with:

• Higher rates of coronary reperfusion (62% with standard regimen vs 73-77% with accelerated regimens) 5
• Lower 30-day mortality (12.7% with standard regimen vs 6.1-6.8% with accelerated regimens) 5
• Better preservation of left ventricular function 2

Post-Fibrinolytic Management

• Transfer to a PCI-capable center immediately after fibrinolysis 1
• Perform angiography and PCI of the infarct-related artery between 2-24 hours after successful fibrinolysis 1
• Emergency angiography and PCI are indicated if:
  • Fibrinolysis fails (<50% ST-segment resolution at 60-90 minutes)
  • Hemodynamic or electrical instability develops
  • Ischemia worsens
  • Evidence of reocclusion after initial successful fibrinolysis 1

Key Pitfalls to Avoid

1. Delay in administration: Fibrinolytic therapy should be initiated as soon as possible after STEMI diagnosis, preferably in the pre-hospital setting 1

2. Improper anticoagulation: Inadequate anticoagulation may lead to reocclusion of the infarct-related artery

3. Using streptokinase in patients with prior exposure: Prior treatment with streptokinase within the previous 6 months is an absolute contraindication due to antibody formation 1

4. Inadequate monitoring: Patients should be monitored closely for signs of reperfusion, reocclusion, and complications

5. Failure to transfer for PCI: All patients should be transferred to a PCI-capable center immediately after fibrinolysis 1