What is the dosage of Lovenox (enoxaparin) for Deep Vein Thrombosis (DVT) prophylaxis and its effect on stroke prevention?

Lovenox (Enoxaparin) for DVT Prophylaxis and Stroke Prevention

For DVT prophylaxis, enoxaparin 40 mg subcutaneously once daily is the standard dosage, while for therapeutic anticoagulation to prevent stroke, the dosage is 1 mg/kg subcutaneously twice daily or 1.5 mg/kg once daily. 1

DVT Prophylaxis Dosing

Enoxaparin is a low-molecular-weight heparin (LMWH) with several advantages over unfractionated heparin, including:

• Better bioavailability and longer half-life 1
• More predictable anticoagulation effect 1
• Lower risk of heparin-induced thrombocytopenia 1
• Once-daily dosing for prophylaxis 1

Standard Prophylactic Dosing:

• Standard dose: 40 mg subcutaneously once daily 1
• Duration: Length of hospital stay or until fully ambulatory for medical patients; at least 7-10 days for surgical patients 1

Special Populations Requiring Dose Adjustments:

1. Obesity:

   • For patients with BMI >30 kg/m², consider:
     • Intermediate doses (40 mg subcutaneously every 12 hours) 1
     • Weight-based dosing (0.5 mg/kg subcutaneously every 12 hours) 1
     • For patients >150 kg, consider 40 mg subcutaneously every 12 hours 1

2. Renal Impairment:

   • For creatinine clearance <30 mL/min: reduce to 30 mg subcutaneously once daily 1
   • Renal clearance of enoxaparin is reduced by 31% in moderate impairment (30-60 mL/min) and 44% in severe impairment (<30 mL/min) 1

3. Very High-Risk Patients:

   • Consider combination with mechanical prophylaxis (pneumatic compression devices) 1

Stroke Prevention and Treatment

Enoxaparin has demonstrated efficacy in preventing stroke and treating venous thromboembolism (VTE) that could lead to stroke:

Therapeutic Dosing for VTE Treatment:

• 1 mg/kg subcutaneously every 12 hours 1
• 1.5 mg/kg subcutaneously once daily 1

Efficacy in Stroke Prevention:

• Enoxaparin has been shown to reduce the risk of venous thromboembolism by 43% compared to unfractionated heparin in patients with acute ischemic stroke 2
• In the PREVAIL study, enoxaparin 40 mg once daily was more effective than unfractionated heparin 5000 U twice daily in preventing VTE after acute ischemic stroke 2
• Another study showed enoxaparin was as safe and effective as unfractionated heparin in preventing thromboembolic events in patients with lower limb paralysis due to acute ischemic stroke 3

Clinical Considerations

Timing of Administration:

• For surgical patients: Start 2-4 hours preoperatively or 10-12 hours preoperatively 1
• For neuraxial anesthesia: Avoid within 10-12 hours before procedure; can resume 6-8 hours postoperatively 1
• For epidural catheter removal: Hold for 24 hours before removal and resume no earlier than 2 hours after removal 1

Monitoring:

• Routine monitoring of anti-Xa levels is not required for most patients 4
• Consider monitoring in patients with renal impairment, obesity, or pregnancy 4
• Target anti-Xa level for prophylaxis: 0.3-0.5 IU/mL 4

Safety Profile:

• Most common adverse events: minor bleeding, hematoma at injection site 5
• Major bleeding complications occur in approximately 1-5% of patients 2, 6
• Significantly lower risk of major bleeding compared to conventional anticoagulation with vitamin K antagonists 1

Common Pitfalls and Caveats

• Timing with neuraxial procedures: Failure to properly time enoxaparin administration with spinal/epidural procedures can increase risk of spinal hematoma 1
• Renal function assessment: Not adjusting dose in patients with renal impairment can lead to drug accumulation and increased bleeding risk 1
• Weight considerations: Standard fixed dosing may be inadequate in obese patients and excessive in very low-weight patients 1
• Monitoring: While routine anti-Xa monitoring is not required, it may be beneficial in special populations to ensure therapeutic levels 4
• Drug interactions: Enoxaparin should be used cautiously with other antiplatelet or anticoagulant medications due to increased bleeding risk 1

Remember that enoxaparin is contraindicated in patients with active major bleeding, history of heparin-induced thrombocytopenia, or hypersensitivity to the drug 1.