How to bridge a patient from Coumadin (warfarin) to Lovenox (enoxaparin) with a factor V issue?

Bridging from Warfarin to Enoxaparin in Patients with Factor V Leiden

For patients with Factor V Leiden who require bridging from warfarin (Coumadin) to enoxaparin (Lovenox), a half-therapeutic dose regimen of enoxaparin (1 mg/kg once daily) is recommended as the most effective and safe approach. 1

Assessment of Thrombotic Risk

• Factor V Leiden mutation increases thrombotic risk but is considered a lower-risk thrombophilia compared to deficiencies of antithrombin, protein C, or protein S 2
• Patients with Factor V Leiden may require hematological consultation to determine their specific thrombotic risk profile 2
• The presence of additional genetic risk factors (such as thrombomodulin gene mutations) can significantly increase thrombotic risk in Factor V Leiden patients 3

Bridging Protocol for Factor V Leiden Patients

Step 1: Discontinue Warfarin

• Stop warfarin 5 days before any planned procedure (if applicable) 2
• Check INR the day before planned procedure to ensure it has decreased to ≤1.5 2

Step 2: Initiate Enoxaparin

• Begin enoxaparin when INR falls below 2.0 1
• Use half-therapeutic dose: 1 mg/kg subcutaneously once daily 1
• For obese patients (BMI ≥40 kg/m²), consider using 0.8 mg/kg every 12 hours 4

Step 3: Monitoring

• Anti-factor Xa monitoring is not routinely required for most patients on enoxaparin 4
• Consider measuring anti-factor Xa levels in patients with severe renal impairment or extreme obesity 4
• Target anti-factor Xa level of 0.5-1.0 if monitoring is performed 2

Step 4: Dose Adjustments for Special Populations

• For patients with renal impairment (CrCl <30 mL/min), reduce dose to 1 mg/kg every 24 hours 4
• For elderly patients (≥75 years), consider dose reduction to 0.75 mg/kg every 12 hours 5
• For patients with both Factor V Leiden and additional thrombophilias, consider more aggressive anticoagulation 3

Duration of Bridging Therapy

• Continue enoxaparin until therapeutic INR is achieved when transitioning back to warfarin 1
• For patients undergoing procedures, resume enoxaparin post-procedure at half-therapeutic dose (0.5 mg/kg twice daily) 1
• When resuming warfarin, overlap with enoxaparin until INR reaches therapeutic range 2

Potential Complications and Management

• Monitor for signs of bleeding (major concern) and thrombosis (less common but serious) 1
• If bleeding occurs, consider protamine sulfate for partial neutralization of enoxaparin 4
• If thrombosis occurs despite prophylaxis (rare), consider checking for additional thrombophilias 3
• Patients with Factor V Leiden may occasionally require fresh-frozen plasma or antithrombin supplementation if they fail to achieve desired anti-Xa levels 2

Follow-up Recommendations

• Regular monitoring of INR when transitioning back to warfarin 2
• Consider specialized anticoagulation management service for complex patients 2
• Evaluate for any signs of recurrent VTE during the transition period 1

This bridging protocol has demonstrated safety and efficacy with very low rates of thrombotic events (0.5%) and severe bleeding (0.5%) in patients requiring interruption of oral anticoagulation 1.