Streptokinase Administration in Pulmonary Embolism
For massive pulmonary embolism with hemodynamic instability (hypotension or shock), administer streptokinase 250,000 IU as a loading dose over 20-30 minutes, followed by 100,000 IU/hour for 12-24 hours, or use the accelerated regimen of 1.5 million IU over 2 hours. 1, 2
Dosing Regimens
Two validated streptokinase regimens exist for PE:
Standard regimen:
- Loading dose: 250,000 IU over 20-30 minutes
- Maintenance: 100,000 IU/hour infusion for 12-24 hours 1, 2
Accelerated regimen:
- 1.5 million IU over 2 hours 1, 3
- This shorter regimen has demonstrated comparable efficacy to the standard protocol 4, 5
Administration Details
- Route: Intravenous via peripheral vein or pulmonary artery catheter (both equally effective) 2
- Adjunctive therapy: Administer hydrocortisone with streptokinase to reduce allergic reactions and prevent circulatory instability 2
- Heparin management: Stop heparin before thrombolysis; resume maintenance heparin after streptokinase infusion when APTT returns to less than twice normal 2
Indications by PE Severity
Massive PE (high-risk):
- Hemodynamic instability with systolic BP <90 mmHg or requiring vasopressors
- Cardiogenic shock
- Persistent arterial hypotension
- This is the primary indication where thrombolysis is first-line treatment 1, 2
Submassive PE (intermediate-risk):
- Right ventricular dysfunction on echocardiography
- Elevated cardiac biomarkers
- No hypotension
- Consider thrombolysis case-by-case, weighing bleeding risk against potential benefit 1, 6, 7
The 2008 ESC guidelines emphasize that contraindications considered absolute in myocardial infarction may become relative in immediately life-threatening high-risk PE 1.
Absolute Contraindications
- Hemorrhagic stroke or stroke of unknown origin at any time
- Ischemic stroke within preceding 6 months
- Central nervous system damage, neoplasms, or structural vascular lesions
- Recent major trauma/surgery/head injury (within 3 weeks)
- Gastrointestinal bleeding within the last month
- Known bleeding diathesis
- Active bleeding
- Prior streptokinase treatment within 6 months (highly antigenic with neutralizing antibodies) 8, 1, 2
Relative Contraindications
- Transient ischemic attack in preceding 6 months
- Oral anticoagulant therapy
- Pregnancy or within 1 week postpartum
- Non-compressible vascular punctures
- Traumatic resuscitation
- Refractory hypertension (systolic BP >180 mmHg)
- Advanced liver disease
- Infective endocarditis
- Active peptic ulcer
- Surgery within preceding 7 days 1, 2
Critical Timing Considerations
- Greatest benefit: Treatment initiated within 48 hours of symptom onset 1
- Still effective: Up to 6-14 days after symptom onset 1, 2
- Mortality risk factors: Delay >6 hours between symptom onset and treatment significantly increases mortality 9
Efficacy and Safety Profile
Streptokinase demonstrates:
- 13% cumulative rate of major bleeding in pooled trial data
- 1.8% rate of intracranial/fatal hemorrhage 1
- 60-68% patency rate (TIMI 2 or 3 flow at 90 minutes) 8
- Comparable efficacy to alteplase when using 2-hour regimens, though alteplase produces faster initial hemodynamic improvement 4
Research shows mortality reduction in massive PE: in one randomized trial, all 4 patients receiving streptokinase survived versus 0/4 receiving heparin alone (p=0.02) 5. The accelerated 1.5 million IU regimen reversed acute pulmonary hypertension and right ventricular dysfunction in 35/40 patients without increasing hemorrhagic complications 9.
Common Pitfalls
- Antigenicity: Streptokinase is highly antigenic; prior exposure within 6 months is an absolute contraindication due to neutralizing antibodies 8, 2
- Allergic reactions: Always co-administer hydrocortisone 2
- Systemic symptoms: Expect fever, chills, and potential hypotension (more common than with alteplase) 2
- Postoperative use: Exercise caution in early postoperative period, but not absolutely contraindicated—assess surgery type and bleeding risk 2