LMWH Dosing for DVT Prophylaxis
For DVT prophylaxis in general surgical and medical patients, enoxaparin 40 mg subcutaneously once daily or dalteparin 5000 units subcutaneously once daily are the recommended standard doses. 1, 2
Standard Prophylactic Dosing Regimens
The following weight-based and fixed-dose regimens are recommended for DVT prophylaxis:
- Enoxaparin 40 mg subcutaneously once daily is the standard prophylactic dose for most patients 3, 1
- Dalteparin 5000 units subcutaneously once daily is an equivalent alternative 3
- Once-daily dosing is preferred over twice-daily administration for prophylaxis, improving patient compliance and reducing nursing burden 1, 4
Key Advantages of LMWH Over Unfractionated Heparin
LMWH offers several clinical benefits that make it the preferred agent:
- Lower risk of heparin-induced thrombocytopenia (HIT) compared to unfractionated heparin 3, 1
- No requirement for routine laboratory monitoring in most patients, reducing healthcare costs 3, 1
- Facilitates outpatient prophylaxis due to simple once-daily subcutaneous administration 1
- Reduced minor bleeding complications such as wound hematomas compared to twice-daily unfractionated heparin 4
Special Population Considerations
Renal Impairment
- In severe renal insufficiency (CrCl <30 mL/min), consider unfractionated heparin 5000 units subcutaneously twice daily instead due to LMWH accumulation risk 3, 1
- If LMWH must be used in renal impairment, reduce enoxaparin to 30 mg subcutaneously once daily for prophylaxis 1, 2
- Measure creatinine clearance before initiating therapy to identify patients requiring dose adjustment 2
Cancer Patients
- LMWH is strongly preferred over unfractionated heparin in cancer patients due to demonstrated mortality benefit 3
- Standard prophylactic doses apply unless treating active thrombosis 3
Pregnant Patients
- LMWH is the anticoagulant of choice over warfarin for both prophylaxis and treatment in pregnancy 3
- Enoxaparin 40 mg once daily or dalteparin 5000 units once daily for antepartum prophylaxis in high-risk patients 3
Critical Pitfalls to Avoid
- Do not use standard prophylactic doses in patients with severe renal impairment (CrCl <30 mL/min) without dose reduction or switching to unfractionated heparin 1, 2
- Do not assume all LMWHs are interchangeable—they differ in molecular weight, half-life, and FDA-approved indications 2
- Do not administer LMWH intravenously—subcutaneous administration is the only appropriate route for prophylaxis 1
- Monitor platelet counts in high-risk patients (prior HIT, prolonged therapy >7 days), though routine monitoring is not required 1