What is the dosing for Lovenox (enoxaparin)?

Enoxaparin Dosing

Enoxaparin dosing depends on the clinical indication: for VTE prophylaxis use 40 mg subcutaneously once daily; for therapeutic anticoagulation (VTE treatment or acute coronary syndrome) use 1 mg/kg subcutaneously every 12 hours; and reduce to 1 mg/kg once daily if creatinine clearance is <30 mL/min. 1, 2, 3

VTE Prophylaxis Dosing

For hospitalized medical or surgical patients requiring thromboprophylaxis:

• Standard dose: 40 mg subcutaneously once daily 1, 2, 3
• Alternative regimen: 30 mg subcutaneously twice daily (particularly for high-risk orthopedic surgery) 2, 3
• Duration: Continue for length of hospital stay or until fully ambulatory; consider extended prophylaxis up to 4 weeks for high-risk patients 1, 3

Renal impairment adjustment:

• If CrCl <30 mL/min: Reduce to 30 mg subcutaneously once daily 3

Obesity considerations:

• For BMI >30 kg/m² or weight >150 kg: Consider 40 mg subcutaneously every 12 hours or weight-based dosing at 0.5 mg/kg every 12 hours 3

Therapeutic Anticoagulation Dosing

For VTE Treatment (DVT/PE)

Standard therapeutic dose: 1 mg/kg subcutaneously every 12 hours 1, 2, 3

• Alternative once-daily regimen: 1.5 mg/kg subcutaneously once daily 1, 2
• However, twice-daily dosing may be safer in cancer patients, as once-daily dosing showed higher rates of recurrent PE (8.3% vs 4.2%) and major bleeding (15% vs 6%) in one study 4

Renal impairment adjustment:

• If CrCl <30 mL/min: Reduce to 1 mg/kg subcutaneously once daily 1, 3, 5
• This 50% dose reduction is critical, as severe renal failure increases bleeding risk 2.25-fold without adjustment 6

For Acute Coronary Syndrome

NSTE-ACS (Non-ST Elevation):

• 1 mg/kg subcutaneously every 12 hours 1, 3
• If CrCl <30 mL/min: 1 mg/kg subcutaneously every 24 hours 1, 3

STEMI with Fibrinolytic Therapy:

• Age <75 years: 30 mg IV bolus, then 1 mg/kg subcutaneously every 12 hours (maximum 100 mg for first 2 doses) 1, 3, 7
• Age ≥75 years: No IV bolus, 0.75 mg/kg subcutaneously every 12 hours (maximum 75 mg for first 2 doses) 1, 3, 7
• Regardless of age, if CrCl <30 mL/min: 1 mg/kg subcutaneously every 24 hours 1

For PCI Support

If patient already on enoxaparin:

• Last dose 8-12 hours ago OR only 1 dose given: 0.3 mg/kg IV bolus 1
• Last dose within 8 hours: No additional dose needed 1

If no prior anticoagulation:

• 0.5-0.75 mg/kg IV bolus 1

Monitoring Requirements

Routine monitoring is generally not required, but anti-Xa monitoring is recommended for: 3

• Pregnant patients on therapeutic doses
• Severe renal impairment (CrCl <30 mL/min) on prolonged therapy
• Morbidly obese patients
• When trough levels suggest accumulation

Target anti-Xa levels:

• Therapeutic twice-daily dosing: 0.5-1.0 IU/mL (peak, measured 4-6 hours post-dose) 3, 6, 5
• Therapeutic once-daily dosing: 1.0-1.5 IU/mL 3

Platelet monitoring:

• Check platelet counts every 2-3 days for first 14 days due to heparin-induced thrombocytopenia risk 3

Critical Pitfalls to Avoid

Do not "stack" enoxaparin with unfractionated heparin - this significantly increases bleeding risk 2

Do not use standard dosing in severe renal impairment - enoxaparin clearance is reduced by 44% when CrCl <30 mL/min, requiring dose reduction 3, 5

Do not exceed maximum doses in elderly patients with fibrinolysis - patients ≥75 years should not receive the IV bolus and should have reduced subcutaneous doses 1, 7

Timing with neuraxial anesthesia: Do not administer prophylactic doses within 10-12 hours before spinal/epidural procedures; wait at least 2 hours after catheter removal before dosing 1