What is the recommended dosing for Lovenox (enoxaparin)?

Lovenox (Enoxaparin) Dosing

Enoxaparin dosing depends on the clinical indication: for DVT prophylaxis use 40 mg subcutaneously once daily (or 30 mg once daily if creatinine clearance <30 mL/min), and for therapeutic anticoagulation use 1 mg/kg subcutaneously every 12 hours or 1.5 mg/kg once daily. 1, 2

DVT Prophylaxis Dosing

Standard Prophylactic Regimens

For moderate-risk patients, administer enoxaparin 40 mg subcutaneously once daily, starting after surgery and continuing for the length of hospital stay or until fully ambulatory. 1, 2

For high-risk surgical patients (such as hip or knee replacement), two equally effective regimens exist:

• 40 mg subcutaneously once daily starting preoperatively 1, 3
• 30 mg subcutaneously every 12 hours starting postoperatively (within 24 hours) 1, 3

Both regimens demonstrated similar efficacy (11-14% DVT incidence) and are superior to lower doses. 3

Renal Impairment Adjustments

For patients with creatinine clearance <30 mL/min, reduce prophylactic dosing to 30 mg subcutaneously once daily. 1, 2 This is critical because enoxaparin clearance is reduced by 44% in severe renal impairment. 2

Obesity Considerations

For patients with BMI >30 kg/m² or body weight >150 kg, consider intermediate-dose prophylaxis of 40 mg subcutaneously every 12 hours or weight-based dosing at 0.5 mg/kg every 12 hours, as standard fixed dosing may be inadequate. 2

Therapeutic Anticoagulation Dosing

Acute Coronary Syndromes

For NSTE-ACS initial therapy, use 1 mg/kg subcutaneously every 12 hours. 1 If creatinine clearance <30 mL/min, reduce to 1 mg/kg subcutaneously every 24 hours. 1

For STEMI with fibrinolytic therapy:

• Age <75 years: 30 mg IV bolus, followed 15 minutes later by 1 mg/kg subcutaneously every 12 hours (maximum 100 mg for first two doses) 1
• Age ≥75 years: No IV bolus; start with 0.75 mg/kg subcutaneously every 12 hours (maximum 75 mg for first two doses) 1

For primary PCI support, administer 0.5 mg/kg IV bolus if no prior anticoagulation, or 0.3 mg IV if last subcutaneous dose was 8-12 hours prior. 1

DVT/PE Treatment

For established DVT or PE, use either:

• 1 mg/kg subcutaneously every 12 hours (preferred for most patients) 2, 4
• 1.5 mg/kg subcutaneously once daily (alternative regimen) 2, 4

Both regimens are equally effective and safe compared to unfractionated heparin, with symptomatic VTE recurrence rates of 2.9-4.4%. 4

For patients with BMI ≥40 kg/m², reduce to 0.8 mg/kg subcutaneously every 12 hours to avoid excessive anticoagulation. 2

For cancer patients requiring extended treatment, continue therapeutic dosing for at least 3-6 months, with consideration for dose reduction after the first month. 2

Timing and Neuraxial Anesthesia

When neuraxial anesthesia is planned, do not administer prophylactic enoxaparin within 10-12 hours before the procedure or catheter manipulation. 1, 2 After catheter removal, wait at least 2 hours before administering enoxaparin, though some guidelines suggest waiting 4-12 hours depending on the dose. 1, 2

For surgical patients, enoxaparin can be started 2-4 hours postoperatively or 10-12 hours preoperatively depending on bleeding risk. 2

Monitoring Requirements

Routine coagulation monitoring is not necessary for most patients, but anti-Xa level monitoring is recommended for:

• Pregnant patients on therapeutic doses 2
• Severe renal impairment on prolonged therapy (target 0.5-1.5 IU/mL) 2
• Morbidly obese patients 2

Measure anti-Xa levels 4-6 hours after dosing, after 3-4 doses have been administered. 2 Target peak anti-Xa levels are 0.6-1.0 IU/mL for twice-daily therapeutic dosing and 1.0-1.5 IU/mL for once-daily dosing. 2

Monitor platelet counts regularly during treatment due to risk of heparin-induced thrombocytopenia, checking at least every 2-3 days for the first 14 days. 2

Critical Cautions

Never switch between enoxaparin and unfractionated heparin during active treatment, as this significantly increases bleeding risk. 2, 5

Enoxaparin is not recommended for thromboprophylaxis in patients with mechanical prosthetic heart valves, as specifically warned by the FDA. 1

Withhold enoxaparin for 2-3 days after major trauma before considering initiation, and only after reassessing the risk-benefit ratio. 1

For elderly patients ≥75 years, dose reduction to 0.75 mg/kg every 12 hours may be necessary for therapeutic anticoagulation to reduce bleeding risk. 5