What is the recommended streptokinase dose and administration regimen for an adult with acute ST‑elevation myocardial infarction?

Streptokinase Dosing for Acute STEMI

The recommended dose of streptokinase for acute ST-elevation myocardial infarction is 1.5 million units administered intravenously over 30-60 minutes, diluted in 100 mL of 5% dextrose or 0.9% saline. 1

Standard Dosing Regimen

• Administer 1.5 million units of streptokinase intravenously over 30-60 minutes 1
• Dilute in 100 mL of 5% dextrose or 0.9% normal saline 1
• The infusion can be safely given over 30 minutes (accelerated regimen) or 60 minutes (standard regimen) with similar safety profiles 2, 3, 4

Adjunctive Anticoagulation

Streptokinase does not require mandatory intravenous heparin co-therapy, unlike fibrin-specific agents 1

• Subcutaneous heparin or no heparin are acceptable options with streptokinase 1
• Intravenous heparin should be given to high-risk patients (large or anterior MI, atrial fibrillation, previous embolus, or known LV thrombus) 1
• If IV heparin is used: 60 U/kg bolus (maximum 4000 U) followed by 12 U/kg/hour infusion (maximum 1000 U/hour), adjusted to maintain aPTT at 1.5-2.0 times control (50-70 seconds) 1, 5

Essential Antiplatelet Therapy

• Aspirin 150-325 mg should be chewed immediately (not enteric-coated), followed by 75-160 mg daily 1
• If oral administration is not possible, give aspirin 250 mg intravenously 1

Accelerated vs. Standard Infusion

Research demonstrates that accelerated streptokinase regimens (over 20-30 minutes) achieve higher reperfusion rates compared to standard 60-minute infusions:

• Accelerated regimens show coronary reperfusion rates of 73.5-77.6% versus 57.1-62.2% with standard infusion 3, 4, 6
• 30-day mortality is significantly lower with accelerated regimens (6.06-6.81%) compared to standard regimens (12.74%) 3
• Despite higher rates of transient hypotension with accelerated infusion (38-44% vs. 20%), this side effect is well-tolerated, self-limited (resolves in 16±6 minutes), and does not adversely affect outcomes 2, 3

Critical Contraindications and Warnings

Streptokinase must never be re-administered because antibodies persist for at least 10 years and can impair its activity 1

• Prior streptokinase or anistreplase administration is an absolute contraindication 1
• If re-infarction occurs requiring repeat fibrinolysis, use alteplase, reteplase, or tenecteplase instead 1

Absolute contraindications include: 1

• Hemorrhagic stroke or stroke of unknown origin at any time
• Ischemic stroke in preceding 6 months
• CNS damage or neoplasms
• Recent major trauma/surgery/head injury (within 3 weeks)
• Gastrointestinal bleeding within the last month
• Known bleeding disorder
• Aortic dissection

Timing Considerations

• Greatest mortality benefit occurs when streptokinase is administered within 2-6 hours of symptom onset 1, 7
• Efficacy decreases substantially after 3 hours from symptom onset 7
• The door-to-needle time goal is ≤30 minutes from hospital arrival 1

Management of Hypotension

Streptokinase-induced hypotension (defined as ≥20% decrease in systolic blood pressure within the first 20 minutes) occurs frequently but is benign: 2

• Maintain the streptokinase infusion speed—do not stop or slow the infusion 2
• Administer rapid infusion of normal saline 6
• Hypotension typically resolves spontaneously without specific therapy 2
• This transient hypotension does not increase risk of cardiogenic shock, mortality, or stroke 2