Enoxaparin Dosing in Acute Coronary Syndrome
The recommended dose of enoxaparin in acute coronary syndrome (ACS) is 1 mg/kg subcutaneously every 12 hours, with dose reduction to 1 mg/kg once daily for patients with creatinine clearance <30 mL/min. 1
Initial Therapy Dosing
- For standard initial therapy in ACS: 1 mg/kg subcutaneously every 12 hours 1
- For patients with renal impairment (CrCl <30 mL/min): Reduce dose to 1 mg/kg subcutaneously once daily 1
- An initial intravenous loading dose of 30 mg has been used in selected patients, though this is not mandatory for all patients 1
Dosing When Supporting PCI
For patients who have received prior enoxaparin treatment and are proceeding to PCI:
- If last subcutaneous dose was administered 8-12 hours earlier or only 1 subcutaneous dose has been given: Administer IV dose of 0.3 mg/kg 1
- If last dose was administered within previous 8 hours: No additional enoxaparin needed 1
- For patients who have not received prior anticoagulant therapy: 0.5-0.75 mg/kg IV bolus 1
Dosing With Fibrinolytic Therapy
- For patients <75 years: 30 mg IV bolus, followed in 15 minutes by 1 mg/kg subcutaneously every 12 hours (maximum 100 mg for first 2 doses) 1
- For patients ≥75 years: No bolus, 0.75 mg/kg subcutaneously every 12 hours (maximum 75 mg for first 2 doses) 1
- Regardless of age, if CrCl <30 mL/min: 1 mg/kg subcutaneously every 24 hours 1
Special Considerations and Cautions
- Accurate weight-based dosing is critical - studies show that approximately 19% of patients receive excess doses (>10 mg above recommended), which significantly increases bleeding risk (43% higher odds of major bleeding) 2
- Elderly patients, those with low body weight, and females are at higher risk of receiving excess doses 2
- Concomitant use of enoxaparin with antiplatelet agents (particularly clopidogrel) increases bleeding risk, especially in older patients 3
- For patients who may require open heart surgery while on enoxaparin, there is an increased risk of re-exploration for postoperative bleeding compared to unfractionated heparin 4
Duration of Therapy
- Enoxaparin should be continued for the duration of hospitalization or until PCI is performed 1
- Premature discontinuation of anticoagulation is associated with a rebound increase in thrombin activity and risk of reinfarction, with greatest risk in the first 4-8 hours after discontinuation 1
Careful attention to proper dosing based on weight and renal function is essential to optimize outcomes while minimizing bleeding complications in patients with ACS receiving enoxaparin 5, 2.