Streptokinase Dosing for Catheter-Directed Thrombolysis
For catheter-directed thrombolysis (CDT) in peripheral arterial or venous thrombosis, streptokinase should be administered at 5,000 units/hour for 24-48 hours via selective intra-arterial infusion, with concurrent heparin 250-500 units/hour. 1
Standard CDT Regimen
The established low-dose selective intra-arterial protocol delivers streptokinase at 5,000 units/hour continuously for 24-48 hours, achieving significant lysis in 80% of cases with acceptable bleeding risk (8% major hemorrhage). 1 This regimen represents the evidence-based approach for peripheral arterial thromboembolic disease treated via catheter-directed techniques.
Key Dosing Parameters
- Initial infusion rate: 5,000 units/hour of streptokinase via selective intra-arterial catheter 1
- Duration: 24-48 hours, adjusted based on angiographic response 1
- Concurrent anticoagulation: Heparin 250-500 units/hour administered simultaneously 1
- Monitoring: Serial angiography to assess clot lysis and determine treatment endpoint 1
Important Distinctions from Systemic Thrombolysis
The CDT dosing differs substantially from systemic streptokinase regimens used for other indications:
- Pulmonary embolism (systemic): 250,000 IU loading dose over 30 minutes, then 100,000 IU/hour for 12-24 hours 2
- STEMI (systemic): 1.5 million units IV over 30-60 minutes 2
- Prosthetic valve thrombosis (systemic): 250,000 IU bolus over 30 minutes, then 100,000 IU/hour 2, 3, 4
The selective low-dose CDT approach (5,000 units/hour) provides superior benefit-risk ratio compared to systemic infusion for peripheral arterial disease, with moderately effective thrombolysis and reduced hemorrhagic complications. 1
Clinical Monitoring During CDT
Coagulation parameters should be measured before infusion, at 4 hours, at 24 hours, and every 24 hours thereafter, though these values do not reliably predict clinical response or bleeding risk. 1 The primary determinant of treatment success and duration is serial angiographic assessment showing progressive clot dissolution.
Minor bleeding from puncture sites occurs in approximately 30% of patients, while major hemorrhage requiring transfusion or surgery develops in 8%. 1
Critical Safety Considerations
Streptokinase is highly antigenic and absolutely contraindicated within 6 months of previous exposure due to risk of severe allergic reactions and treatment failure from neutralizing antibodies. 2 For patients with prior streptokinase exposure, urokinase (4,400 IU/kg/hour) or tissue plasminogen activator should be substituted. 2
Absolute contraindications include: any prior intracranial hemorrhage, known cerebrovascular malformation, intracranial neoplasm, ischemic stroke within 3 months, active bleeding, recent major trauma/surgery within 3 weeks, and severe uncontrolled hypertension. 2
Alternative Urokinase Regimen for CDT
Urokinase may be administered at 4,400 IU/kg/hour for 12-24 hours as an alternative to streptokinase for catheter-directed therapy, particularly in patients with prior streptokinase exposure or known allergy. 2 This agent lacks the antigenic properties of streptokinase and can be safely re-administered.
Common Pitfall to Avoid
Do not use systemic high-dose streptokinase regimens (250,000 IU bolus + 100,000 IU/hour) for catheter-directed peripheral arterial thrombolysis. The selective low-dose intra-arterial approach (5,000 units/hour) achieves comparable efficacy with significantly lower systemic fibrinolytic effects and reduced bleeding complications. 1 The higher systemic doses are reserved for pulmonary embolism, myocardial infarction, and prosthetic valve thrombosis where systemic fibrinolysis is the therapeutic goal.