How to dilute streptokinase (SK) injection for intravenous (IV) administration?

Streptokinase Injection Dilution Protocol

Streptokinase should be administered as 1.5 million units diluted in 100 mL of normal saline and infused intravenously over 30-60 minutes for acute myocardial infarction. 1, 2

Dilution and Administration Procedure

For Acute Myocardial Infarction

1. Reconstitute streptokinase powder with the appropriate diluent as per manufacturer's instructions
2. Dilute the reconstituted streptokinase to a total volume of 100 mL with normal saline
3. Administer the 1.5 million units intravenously over 30-60 minutes 1
   • Some evidence suggests that more rapid infusion (20 minutes) may lead to higher reperfusion rates (80% vs 58% with standard 60-minute infusion) 3

For Arterial Thrombosis

• For selective intra-arterial infusion: 5,000 units/hour for 24-48 hours 4, 5
• Often administered with concurrent heparin (250-500 units/hour) 4

For Prosthetic Valve Thrombosis

• Initial bolus: 250,000 units given over 30 minutes
• Followed by continuous infusion: 100,000 units/hour 1
• Duration depends on clinical response (typically 2-72 hours)

Monitoring During Administration

1. Monitor hemodynamic parameters every 2-3 hours during infusion
2. For obstructive prosthetic valve thrombosis, perform Doppler echocardiography every 2-3 hours
3. For non-obstructive cases, perform TEE at 24 hours and repeat at 48 and 72 hours if thrombus persists
4. Monitor for lytic state: increased D-dimer and aPTT, decreased fibrinogen 1

Important Precautions

Contraindications

• Prior streptokinase exposure within the past 6 months (absolute contraindication) 1, 2
• History of streptococcal pharyngitis within past 6 months 1
• Other standard contraindications for thrombolytic therapy include:
  • Active bleeding or bleeding diathesis
  • Recent stroke (within 3 months)
  • Intracranial or intraspinal surgery within 2 months
  • Suspected aortic dissection
  • Significant head/facial trauma within 3 months 1

Adjunctive Medications

• Administer aspirin (150-325 mg orally or 250-500 mg IV) before streptokinase 2
• For STEMI, add clopidogrel (300 mg loading dose if ≤75 years; 75 mg if >75 years) 2
• Anticoagulation should be administered with streptokinase:
  • Unfractionated heparin: 60 U/kg IV bolus (maximum 4000 U) followed by infusion of 12 U/kg/hr (maximum 1000 U/hr) 1, 2
  • Or fondaparinux: 2.5 mg IV bolus followed by 2.5 mg SC once daily 1, 2

Clinical Pearls

• Streptokinase is non-fibrin specific and achieves 60-68% patency rates (TIMI 2-3 flow) at 90 minutes, which is lower than fibrin-specific agents like alteplase (73-84%) or tenecteplase (85%) 1, 2
• Streptokinase antibodies can persist for years after exposure, potentially reducing efficacy and increasing allergic reaction risk 2
• For prosthetic valve thrombosis, if there's no hemodynamic improvement after 24 hours or after 72 hours even without complete recovery, consider stopping the infusion 1
• If streptokinase fails due to antibodies, consider switching to urokinase 1
• Surgery can be performed 24 hours after discontinuation of streptokinase infusion 1

By following this protocol, you can safely and effectively administer streptokinase for thrombolysis in appropriate clinical scenarios while minimizing complications.