What is the typical dosage of Enoxaparin (low molecular weight heparin) for the prevention and treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE)?

Enoxaparin Dosing for DVT and PE Prevention and Treatment

Prophylactic Dosing (DVT Prevention)

For DVT prophylaxis in medical and surgical patients, administer enoxaparin 40 mg subcutaneously once daily, starting 2-4 hours preoperatively or within 24 hours of hospital admission, and continuing throughout hospitalization or until the patient is fully ambulatory. 1

• The standard prophylactic dose is 40 mg subcutaneously once daily for most medical and surgical patients 2, 1
• Duration should extend for the entire hospital stay or until full ambulation for medical patients, and at least 7-10 days for surgical patients 1
• An alternative regimen of 30 mg subcutaneously every 12 hours has demonstrated superior efficacy in knee arthroplasty when started 12-24 hours post-surgery 1

Dose Adjustments for Special Populations

Renal Impairment:

• For severe renal insufficiency (creatinine clearance <30 mL/min), reduce the prophylactic dose to 30 mg subcutaneously once daily 1, 3
• Enoxaparin clearance is reduced by 31% in moderate renal impairment and 44% in severe renal impairment 1

Obesity:

• For patients with BMI >30 kg/m², consider intermediate doses of 40 mg subcutaneously every 12 hours or weight-based dosing at 0.5 mg/kg subcutaneously every 12 hours 1, 3
• For patients weighing >150 kg at high risk, increase to 40 mg every 12 hours 3

Therapeutic Dosing (DVT/PE Treatment)

For treatment of established DVT or PE, administer enoxaparin 1 mg/kg subcutaneously every 12 hours, which is the preferred regimen providing consistent therapeutic anticoagulation with proven efficacy equivalent to unfractionated heparin. 1

• Primary regimen: 1 mg/kg subcutaneously every 12 hours 2, 1, 3
• Alternative regimen: 1.5 mg/kg subcutaneously once daily 2, 1, 3
• Initial treatment typically lasts 5-10 days, overlapping with warfarin until INR >2.0 for 2 consecutive days 1

Therapeutic Dose Adjustments

Renal Impairment:

• For severe renal insufficiency (creatinine clearance <30 mL/min), reduce therapeutic dose to 1 mg/kg subcutaneously every 24 hours 3

Obesity:

• For patients with BMI ≥40 kg/m², use 0.8 mg/kg subcutaneously every 12 hours 1

Cancer Patients:

• For cancer patients requiring extended treatment, continue enoxaparin for at least 3-6 months for DVT and 6-12 months for PE 2
• Long-term dosing: 200 U/kg (approximately 2 mg/kg) subcutaneously daily for 1 month, then 150 U/kg (approximately 1.5 mg/kg) subcutaneously daily 2

Monitoring Recommendations

Anti-Xa Level Monitoring:

• Monitor anti-Xa levels in patients with severe renal impairment on prolonged therapy, targeting 0.5-1.5 IU/mL 1
• Measure anti-Xa levels 4-6 hours after dosing, after the patient has received 3-4 doses 1
• Target peak anti-Xa level is 1.0-1.5 IU/mL for once-daily dosing and 0.6-1.0 IU/mL for twice-daily dosing 1
• Routine monitoring is generally not necessary except in pregnant patients on therapeutic doses, obesity, and renal impairment 1, 3

Platelet Monitoring:

• Monitor platelet counts every 2-3 days from day 4 to day 14 to screen for heparin-induced thrombocytopenia 1, 3
• Baseline laboratory testing should include CBC, renal and hepatic function panel, aPTT, and PT/INR 1

Critical Timing Considerations with Neuraxial Anesthesia

To prevent spinal hematoma, avoid enoxaparin administration within 10-12 hours before neuraxial anesthesia or spinal catheter removal. 1

• For prophylactic doses (40 mg once daily), enoxaparin may be started as early as 4 hours after catheter removal but not earlier than 12 hours after the block was performed 1, 3
• For intermediate (40 mg every 12 hours) or therapeutic doses, enoxaparin may be started as early as 4 hours after catheter removal but not earlier than 24 hours after the block 3

Common Pitfalls and Caveats

• Failure to adjust dosing in renal impairment leads to drug accumulation and significantly increased bleeding risk due to 44% reduction in clearance 1
• Standard fixed dosing may be inadequate in obese patients and excessive in very low-weight patients, requiring weight-based adjustments 1
• Not properly timing administration with spinal/epidural procedures increases the risk of spinal hematoma 1
• Enoxaparin is primarily eliminated renally, not hepatically, making elevated liver enzymes alone insufficient reason to avoid use, though moderate-to-severe liver disease with coagulopathy remains a contraindication 1
• Avoid switching between enoxaparin and unfractionated heparin due to increased bleeding risk 1