What is the recommended dose of Enoxaparin (Low Molecular Weight Heparin) for a patient with Deep Vein Thrombosis (DVT)?

Enoxaparin Dosing for DVT Treatment

For treatment of acute DVT in adults, administer enoxaparin 1 mg/kg subcutaneously every 12 hours or 1.5 mg/kg subcutaneously once daily, with both regimens demonstrating equivalent efficacy. 1, 2

Standard Therapeutic Dosing Regimens

The preferred dosing is 1 mg/kg subcutaneously every 12 hours, which provides consistent therapeutic anticoagulation with proven efficacy equivalent to unfractionated heparin for preventing recurrent symptomatic VTE and major hemorrhage. 1, 2, 3 The twice-daily regimen may be more efficacious in certain populations, though once-daily dosing at 1.5 mg/kg offers advantages including improved patient compliance, reduced healthcare worker exposure, fewer injections, and potentially lower treatment costs. 1, 2

Both regimens have been validated in large randomized controlled trials showing equivalent safety and efficacy, with symptomatic VTE recurrence rates of 2.9% for twice-daily dosing and 4.4% for once-daily dosing compared to 4.1% for unfractionated heparin. 3

Critical Dose Adjustments

Obesity (BMI ≥40 kg/m²)

Reduce dose to 0.8 mg/kg subcutaneously every 12 hours for patients with BMI ≥40 kg/m², as standard fixed dosing may be inadequate in obese patients and excessive in very low-weight patients. 2, 4

Severe Renal Impairment (CrCl <30 mL/min)

Dose reduction is mandatory due to 2-3 fold increased bleeding risk. 2, 4 Enoxaparin clearance is reduced by 31% in moderate renal impairment and 44% in severe renal impairment. 1, 2 For prophylactic dosing in severe renal insufficiency, reduce to 30 mg subcutaneously once daily, but therapeutic dosing requires careful individualized adjustment with anti-Xa monitoring. 1

Cancer Patients

Administer 1 mg/kg subcutaneously every 12 hours for patients with BMI <40 kg/m², with extended treatment duration of at least 3-6 months recommended. 2, 4 Consider dose reduction after the first month for long-term therapy. 2 Dalteparin at 200 units/kg daily for 30 days, then 150 units/kg daily, is an alternative with the highest quality evidence and FDA approval specifically for cancer-associated VTE. 4

Treatment Duration

• Initial treatment typically lasts 5-10 days, overlapping with warfarin until INR >2.0 for 2 consecutive days if transitioning to oral anticoagulation. 1, 2
• Cancer patients require extended treatment for at least 3-6 months, and indefinitely while cancer remains active or under treatment. 1, 2
• Provoked DVT (reversible risk factor): Treat for exactly 3 months. 1
• Unprovoked DVT: Treat for minimum 3-6 months initially, then consider indefinite continuation. 1

Monitoring Requirements

Baseline Testing

Obtain CBC, renal and hepatic function panel, aPTT, and PT/INR before initiating therapy. 2

Follow-up Monitoring

• Monitor hemoglobin, hematocrit, and platelet count every 2-3 days for the first 14 days, then every 2 weeks thereafter or as clinically indicated. 2
• Platelet monitoring from day 4 to day 14 is essential to screen for heparin-induced thrombocytopenia. 1, 2
• Anti-Xa level monitoring is not routinely necessary for most patients, but is indicated for pregnant patients on therapeutic doses and patients with severe renal impairment on prolonged therapy (target 0.5-1.5 IU/mL, measured 4-6 hours after dosing). 1

Pediatric Dosing

For children >5 years, administer 1 mg/kg subcutaneously every 12 hours, with dose titration to achieve peak anti-Xa level of 0.5-1.0 IU/mL. 5, 2 The first anti-Xa level should be checked 4 hours after the second or third dose. 5

Common Pitfalls and Caveats

• Never switch between enoxaparin and unfractionated heparin due to increased bleeding risk. 1, 2
• Failure to adjust dose in renal impairment leads to drug accumulation and increased bleeding risk—always check creatinine clearance before initiating therapy. 1, 2
• Not adjusting for obesity (BMI ≥40 kg/m²) results in inadequate anticoagulation. 2
• Enoxaparin should be used cautiously with other antiplatelet or anticoagulant medications due to increased bleeding risk. 1
• Avoid administration within 10-12 hours before neuraxial anesthesia to prevent spinal hematoma. 1
• Enoxaparin is primarily eliminated renally, not hepatically, so elevated liver enzymes alone do not require dose adjustment unless there is hepatic coagulopathy. 1