Enoxaparin Dosing for Bridging to Therapeutic Warfarin INR
The recommended dosing for enoxaparin as a bridge to therapeutic warfarin INR is 1 mg/kg subcutaneously every 12 hours until the INR reaches the therapeutic range (typically 2-3), with dose adjustments based on renal function and patient characteristics. 1, 2
Standard Bridging Protocol
Initial Dosing
- Standard therapeutic dose: 1 mg/kg subcutaneously every 12 hours 1, 2
- Alternative regimen: 1.5 mg/kg subcutaneously once daily 1, 2
Special Population Adjustments
- Patients ≥75 years: Consider reducing dose to 0.75 mg/kg subcutaneously every 12 hours 3
- Renal impairment (CrCl <30 mL/min): Reduce to 1 mg/kg subcutaneously once daily 1, 2
- Obesity (BMI >40): Consider monitoring anti-Xa levels to ensure appropriate dosing 2
Duration of Bridging Therapy
Bridging therapy should continue until the INR reaches the therapeutic range (typically 2-3) for two consecutive days 2. This usually takes approximately 5-7 days of overlapping therapy.
Monitoring During Bridging
- Check INR daily while bridging until therapeutic for two consecutive days 2
- Monitor platelet counts periodically to detect heparin-induced thrombocytopenia 2
- Anti-Xa monitoring is generally not required for most patients but may be considered in:
- Severe renal insufficiency
- Morbid obesity
- Pregnancy
- Pediatric patients 2
Alternative Bridging Approaches
For patients at lower risk of thromboembolism, a half-therapeutic dose regimen may be considered:
- 1 mg/kg subcutaneously once daily (instead of twice daily) 4
- This approach has shown similar efficacy with potentially reduced bleeding risk in selected patients 4
Potential Complications and Management
Bleeding Risk
- Major bleeding occurs in approximately 0.5-1% of patients on therapeutic enoxaparin bridging 4
- Risk factors include:
- Concomitant antiplatelet therapy
- Recent surgery
- Advanced age
- Renal impairment 2
Wound Healing
- Bridging therapy with enoxaparin and warfarin may delay wound healing compared to warfarin alone in post-surgical patients 5
- Consider the risk-benefit ratio in post-surgical patients, especially after orthopedic procedures 5
Practical Implementation
- Start warfarin on the same day as enoxaparin
- Continue enoxaparin at full therapeutic dose until INR ≥2.0 for two consecutive days
- Discontinue enoxaparin when INR is therapeutic (2-3)
- For patients with high bleeding risk, consider discontinuing enoxaparin when INR reaches 1.8-2.0 2
This approach ensures adequate anticoagulation during the transition period while minimizing the risk of both thromboembolism and bleeding complications.