From the Guidelines
For STEMI, enoxaparin should be administered as a 30 mg intravenous (IV) bolus, followed by 1 mg/kg subcutaneously every 12 hours, with dose adjustments for renal impairment and elderly patients, as recommended by the most recent guidelines 1.
Enoxaparin Dosing for STEMI
The dosing of enoxaparin for STEMI patients is as follows:
- For patients less than 75 years of age, an initial 30 mg intravenous bolus is given, followed by 1 mg/kg subcutaneously every 12 hours.
- For patients at least 75 years of age, the initial intravenous bolus is eliminated, and the subcutaneous dose is reduced to 0.75 mg/kg every 12 hours.
- Regardless of age, if the creatinine clearance is estimated to be less than 30 mL per minute, the subcutaneous regimen is 1 mg/kg every 24 hours.
Rationale for Enoxaparin Use
Enoxaparin works by enhancing the inhibitory effect of antithrombin on factor Xa and thrombin, preventing clot formation and extension. This anticoagulation is crucial in STEMI to prevent further thrombosis at the site of plaque rupture and to reduce the risk of recurrent ischemic events.
Important Considerations
- Blood counts should be monitored during therapy to watch for bleeding complications.
- Concomitant use with other antiplatelet or anticoagulant medications requires careful consideration.
- The most recent guidelines recommend enoxaparin as an alternative to unfractionated heparin for STEMI patients, with a predictable dose response and reduced risk of heparin-induced thrombocytopenia 1.
From the Research
Enoxaparin Dosing for STEMI
- The recommended dose of enoxaparin for patients with ST-segment elevation myocardial infarction (STEMI) is an initial 30 mg intravenous bolus, followed by 1 mg/kg subcutaneously within 15 minutes and then every 12 hours for up to 8 days 2, 3.
- The first two subcutaneous dosages should not exceed 100 mg 2, 3.
- For patients aged 75 years or older, the initial bolus of enoxaparin should be omitted, and the 12-hourly dosages should be reduced to 0.75 mg/kg 2, 3.
- For patients with an estimated creatinine clearance of less than 30 mL/min, the dose of enoxaparin should be reduced to 1 mg/kg every 24 hours 2, 3.
Efficacy and Safety of Enoxaparin in STEMI
- Enoxaparin has been shown to be more effective than unfractionated heparin (UFH) in reducing the risk of death or recurrent myocardial infarction in patients with STEMI 2, 3, 4, 5, 6.
- Enoxaparin has also been associated with a reduction in ischemic complications, including death, recurrent myocardial infarction, and urgent revascularization 2, 3, 6.
- However, enoxaparin has been associated with an increased risk of bleeding compared to UFH 2, 3, 4, 5.
- Despite this, enoxaparin has been shown to have a net clinical benefit compared to UFH in patients with STEMI 2, 3.