Is Lovenox (enoxaparin) administered intravenously (IV) or subcutaneously (subq) for pulmonary embolism?

Lovenox (Enoxaparin) Administration for Pulmonary Embolism

Lovenox (enoxaparin) is administered subcutaneously (subq), not intravenously (IV), for the treatment of pulmonary embolism. 1

Evidence-Based Administration Route

The European Society of Cardiology (ESC) guidelines clearly specify that enoxaparin is administered subcutaneously for pulmonary embolism treatment. The guidelines provide specific dosing recommendations:

• Enoxaparin 1.0 mg/kg subcutaneously every 12 hours
• Enoxaparin 1.5 mg/kg subcutaneously once daily 1

These subcutaneous regimens have been extensively studied and are approved for the treatment of pulmonary embolism.

Dosing Considerations

When administering enoxaparin for pulmonary embolism:

• The standard treatment dose is 1 mg/kg subcutaneously every 12 hours or 1.5 mg/kg subcutaneously once daily
• Once-daily injection of enoxaparin at 1.5 mg/kg is approved for inpatient treatment of PE in the United States and some European countries 1
• Dose adjustments are needed for patients with severe renal impairment (creatinine clearance <30 mL/min) 1

Clinical Evidence

Clinical trials have demonstrated that subcutaneous enoxaparin is as effective and safe as intravenous unfractionated heparin for pulmonary embolism treatment:

• A randomized controlled trial of 900 patients with venous thromboembolism (including 32% with confirmed pulmonary embolism) showed equivalent efficacy between subcutaneous enoxaparin (both once and twice daily regimens) and intravenous unfractionated heparin 2
• Recurrence rates were 4.4% for once-daily subcutaneous enoxaparin, 2.9% for twice-daily subcutaneous enoxaparin, and 4.1% for IV unfractionated heparin 2

Treatment Duration and Monitoring

• Anticoagulation with enoxaparin should be continued for at least 5 days and until the INR is between 2.0-3.0 for at least 2 consecutive days when transitioning to a vitamin K antagonist 1
• Anti-Xa monitoring is not routinely required but should be considered in patients with severe renal impairment or during pregnancy 1
• The target anti-Xa range is 0.6-1.0 IU/mL for twice-daily administration and 1.0-2.0 IU/mL for once-daily administration 1

Important Considerations and Potential Pitfalls

• Critical illness impact: Critically ill patients may have lower anti-Xa levels with standard subcutaneous dosing compared to non-critically ill patients, potentially requiring dose adjustment or monitoring 3
• Bleeding risk: While rare, serious bleeding complications including hemothorax and retroperitoneal hematoma have been reported with enoxaparin therapy 4
• Weight considerations: Peak anti-Xa activities are negatively correlated with body mass index, suggesting that dosing adjustments may be needed in obese patients 3
• Renal function: Dose reduction is necessary in patients with severe renal impairment (creatinine clearance <30 mL/min) due to drug accumulation risk 1

In summary, enoxaparin is administered exclusively via the subcutaneous route for pulmonary embolism treatment, with established efficacy and safety compared to intravenous unfractionated heparin.