Timing of LMWH (Lomoh/Enoxaparin) Administration After Streptokinase
For patients receiving streptokinase for acute myocardial infarction, administer enoxaparin as a 30-40 mg intravenous bolus immediately before or during streptokinase infusion, followed by 1 mg/kg subcutaneously every 12 hours starting after the streptokinase infusion is complete, continuing for 5-7 days. 1, 2
Optimal Timing Protocol
Immediate Administration Strategy
- Give enoxaparin 30-40 mg IV bolus before starting streptokinase infusion to establish immediate anticoagulation coverage 1, 2
- Begin subcutaneous enoxaparin 1 mg/kg every 12 hours immediately after streptokinase infusion completes (not 4 hours later as with unfractionated heparin) 1, 3
- Continue this regimen for 5-7 days to prevent reocclusion 1, 2
Evidence Supporting Early Administration
The research demonstrates that combining enoxaparin with streptokinase (rather than waiting) produces superior outcomes:
- Coronary reperfusion rates of 78.4% with immediate enoxaparin versus 62.2% with delayed unfractionated heparin 1
- 30-day mortality significantly lower at 6.3% with enoxaparin versus 12.7% with traditional delayed heparin approach 1
- Reocclusion rates dramatically reduced: 0% with enoxaparin versus 5.7% with unfractionated heparin 2
- Recurrent ischemia less frequent (18.8% versus 40.6%) when enoxaparin given simultaneously rather than delayed 3
Critical Timing Distinctions
This is NOT Perioperative Bridging
The perioperative guidelines about waiting 24-72 hours before LMWH administration do not apply to post-thrombolytic therapy 4. Those recommendations address surgical bleeding risk, which is fundamentally different from the thrombotic emergency of acute MI 4, 5.
Why Immediate Administration Works
- Streptokinase creates a prothrombotic state requiring immediate anticoagulation coverage 1
- The predictable anticoagulant effect of enoxaparin (versus unfractionated heparin) prevents the "anticoagulation gap" that leads to reocclusion 1
- Early administration during the critical first hours prevents thrombus reformation while fibrinolysis is occurring 2, 3
Dosing Regimen Details
Standard Protocol
- Initial IV bolus: 30-40 mg enoxaparin given before or with streptokinase 1, 2
- Maintenance: 1 mg/kg subcutaneously every 12 hours for 5-7 days 1
- All patients should receive aspirin 250-325 mg daily concurrently 1
Renal Adjustment
- If creatinine clearance <30 mL/min, reduce to once-daily dosing or consider unfractionated heparin instead 4, 6
Safety Profile
Bleeding Risk
- Major hemorrhagic events are similar between enoxaparin and unfractionated heparin regimens (no significant difference) 1, 2
- Hypotension during infusion occurs more frequently with streptokinase (31.4%) but resolves without consequence 2
- No increase in intracranial hemorrhage with immediate enoxaparin administration 1, 2
Common Pitfall to Avoid
Do not wait 24 hours after streptokinase to start LMWH as you would after thrombolysis for stroke 4. The stroke guideline specifically states "prophylactic-dose heparin should not be used within the first 24 hours after administration of thrombolytic therapy" 4, but this refers to prophylactic dosing for DVT prevention in stroke patients, not therapeutic anticoagulation for acute MI where the pathophysiology and goals are entirely different.
The key distinction: In acute MI post-streptokinase, you are treating the culprit coronary thrombus and preventing reocclusion, which requires immediate therapeutic anticoagulation. In stroke, you are preventing DVT complications, which can be safely delayed 4.