What is the recommended Low Molecular Weight Heparin (LMWH) dose for Deep Vein Thrombosis (DVT) treatment?

LMWH Dosing for DVT Treatment

For acute DVT treatment, use enoxaparin 1 mg/kg subcutaneously every 12 hours OR 1.5 mg/kg subcutaneously once daily, or dalteparin 200 units/kg subcutaneously once daily (maximum 18,000 units), with treatment duration of at least 5-7 days overlapping with warfarin initiation. 1, 2

Standard Treatment Dosing Regimens

Enoxaparin

• 1 mg/kg subcutaneously every 12 hours (preferred for acute treatment) 1
• Alternative: 1.5 mg/kg subcutaneously once daily 1, 3
• The twice-daily regimen may be more efficacious, though once-daily dosing has demonstrated effectiveness in outpatient settings 1, 3

Dalteparin

• 200 units/kg subcutaneously once daily for initial treatment 1, 2, 4
• Maximum dose: 18,000 units per injection 2
• FDA-approved for both initial and extended VTE treatment 1, 2

Tinzaparin

• 175 units/kg subcutaneously once daily 1, 4
• Currently FDA-approved only for immediate VTE treatment, not prophylaxis 1

Duration of Initial Treatment

• Minimum 5-7 days of LMWH therapy required before transitioning to oral anticoagulation 1
• Continue LMWH until INR reaches therapeutic range (2.0-3.0) for at least 24 consecutive hours if transitioning to warfarin 1
• Overlap with warfarin must occur for the entire initial treatment period 1

Special Population Dosing Adjustments

Severe Renal Insufficiency (CrCl <30 mL/min)

• Enoxaparin: Reduce to 1 mg/kg subcutaneously every 24 hours (instead of every 12 hours) 1
  • Standard doses carry 2-3 fold increased bleeding risk in this population 1, 5
  • Some evidence suggests dose reduction even at CrCl 30-60 mL/min 1
• Dalteparin: May have better renal clearance profile; monitor peak anti-Xa levels if CrCl <30 mL/min 5, 2

Obesity (BMI ≥40 kg/m²)

• Enoxaparin: Consider 0.8 mg/kg subcutaneously every 12 hours 5
• Weight-based dosing remains appropriate but institutional protocols should guide extreme obesity management 1

Cancer Patients (Extended Treatment)

• Dalteparin is the only FDA-approved LMWH for extended cancer-associated VTE treatment 1, 5, 2
  • Month 1: 200 units/kg subcutaneously once daily 5, 2
  • Months 2-6: Reduce to 150 units/kg subcutaneously once daily 5, 2
• This regimen reduces VTE recurrence from 15.8% to 8.0% compared to warfarin (HR 0.48, P=0.002) without increasing bleeding 5

Comparative Efficacy

All three LMWHs (enoxaparin, dalteparin, tinzaparin) demonstrate equivalent efficacy and safety for DVT treatment when used at recommended doses 4. A head-to-head trial of tinzaparin versus dalteparin in 505 patients (including 113 with cancer) showed no significant differences in VTE recurrence or bleeding 1, 4.

Critical Monitoring Parameters

• Platelet count: Monitor for heparin-induced thrombocytopenia, particularly in first 2 weeks 2
• Renal function: Assess creatinine clearance before initiating therapy and periodically during treatment 1, 2
• Anti-Xa levels: Generally not required except in severe renal impairment (CrCl <30 mL/min), extreme obesity, or pregnancy 1
• Signs of bleeding: Daily assessment for major or clinically relevant bleeding 2

Common Pitfalls to Avoid

• Do NOT use intramuscular injection - LMWH must be given subcutaneously only 2
• Do NOT mix with other medications in the same syringe 2
• Do NOT use standard doses in severe renal impairment without dose adjustment, particularly with enoxaparin 1, 5
• Do NOT assume all LMWHs are interchangeable - they differ in molecular weight, half-life, and FDA approvals 1
• Do NOT use LMWH for extended cancer-associated VTE treatment unless using dalteparin, which has specific FDA approval and dosing evidence 1, 5, 2