Can a repeat dose of streptokinase be given if the initial infusion fails to achieve reperfusion?

Repeat Dosing of Streptokinase After Failed Reperfusion

Streptokinase should NOT be re-administered if the initial infusion fails to achieve reperfusion—instead, proceed immediately to rescue PCI or switch to a non-immunogenic fibrin-specific agent (alteplase, reteplase, or tenecteplase). 1, 2, 3, 4

Why Re-administration Is Contraindicated

Antibody formation makes repeat streptokinase ineffective and dangerous:

• Neutralizing antibodies develop as early as 4 days after the first dose and persist for at least 4–10 years in up to 50% of patients 2, 3, 4, 5
• These antibodies can neutralize a second dose, rendering it therapeutally ineffective for achieving coronary reperfusion 5
• Re-administration carries an increased risk of severe allergic reactions including anaphylaxis 1, 2, 4, 5
• The ACC/AHA explicitly states: "Streptokinase should not be readministered to treat recurrent ischemia/infarction in patients who received a non-fibrin-specific fibrinolytic agent more than 5 days previously" (Class III recommendation) 1

Recommended Management After Failed Streptokinase

Assessment of Reperfusion Failure (60–90 minutes post-infusion)

Failed reperfusion is defined by:

• Less than 50% ST-segment resolution in the lead showing greatest initial ST elevation 1, 3
• Persistent chest pain or hemodynamic instability 1
• Electrical instability or sustained ventricular arrhythmias 3

Immediate Action: Rescue PCI

Rescue PCI is the Class I recommendation for failed fibrinolysis 1, 3:

• Transfer immediately to a PCI-capable center if not already there 1, 3
• Target rescue PCI within 60 minutes of recognizing reperfusion failure 1
• Rescue PCI reduces mortality and reinfarction compared to repeat thrombolysis or conservative management in moderate- to high-risk patients 1

Additional indications for urgent rescue PCI include:

• Cardiogenic shock (especially if patient <75 years old) 1
• Hemodynamic instability 1, 3
• Large area of myocardium at risk (anterior MI, extensive ST elevation) 1

Alternative: Switch to Non-Immunogenic Fibrinolytic

If rescue PCI is truly unavailable and re-occlusion occurs early:

• Administer a fibrin-specific agent (alteplase, reteplase, or tenecteplase) rather than repeat streptokinase 1, 3, 4
• This is a Class IIa recommendation for patients not candidates for revascularization who have recurrent ST elevation and ischemic chest pain 1
• The ACC/AHA guidelines state: "It is reasonable to (re)administer fibrinolytic therapy to patients with recurrent ST elevation...who are not considered candidates for revascularization" 1

Critical Pitfalls to Avoid

Never re-administer streptokinase in these scenarios:

• Any prior streptokinase or anistreplase exposure (antibodies persist ≥10 years) 2, 3, 4, 5
• More than 5 days after initial streptokinase dose (Class III contraindication) 1
• When a fibrin-specific agent is available as a safer alternative 3, 4

One small observational study from 1995 reported successful repeat streptokinase dosing in 7 patients within 1:45–50 hours without complications 6, but this contradicts all major guideline recommendations and the known immunogenicity profile of streptokinase. This approach cannot be recommended given the strong consensus against re-administration in contemporary guidelines 1, 2, 3, 4.

Optimal Strategy Summary

1. Assess reperfusion at 60–90 minutes using ST-segment resolution and clinical criteria 1, 3
2. If <50% ST resolution or ongoing ischemia: escalate medical therapy (IV nitrates, beta-blockers, anticoagulation) and arrange immediate rescue PCI 1, 3
3. If rescue PCI unavailable: consider switching to alteplase, reteplase, or tenecteplase—never repeat streptokinase 1, 3, 4
4. All patients should be transferred to a PCI-capable center after fibrinolysis for possible rescue or routine angiography within 2–24 hours 1, 3