Transition from Enoxaparin (Lovenox) to Warfarin
Start warfarin concurrently with enoxaparin at 2.5-5 mg daily, continue both agents for a minimum of 5 days AND until INR ≥2.0 for at least 24 hours, then discontinue enoxaparin. 1
Dosing Protocol
Enoxaparin Dosing During Transition
- Continue enoxaparin 1 mg/kg subcutaneously every 12 hours throughout the overlap period 1
- Alternatively, 1.5 mg/kg once daily can be used for outpatient DVT treatment, though the guideline-recommended dose for transition is the twice-daily regimen 1, 2
Warfarin Initiation
- Start warfarin at 2.5-5 mg orally once daily on the same day as enoxaparin 1
- Lower starting doses (2.5 mg) should be considered in elderly patients, those with poor nutritional status, concurrent medications affecting metabolism, or underlying liver disease 1
- Subsequent warfarin dosing is adjusted based on INR values with a target INR of 2-3 1
Overlap Duration Requirements
The critical overlap period requires BOTH conditions to be met:
- Minimum 5 days of concurrent therapy (can extend to 10 days if needed) 1
- INR ≥2.0 for at least 24 hours before discontinuing enoxaparin 1
This dual requirement is essential because warfarin initially depletes protein C and S (natural anticoagulants) before adequately reducing clotting factors, potentially creating a transient hypercoagulable state if enoxaparin is stopped prematurely 3.
INR Monitoring Schedule
- Check INR on day 3 of warfarin therapy 4
- Recheck on day 5 4
- Continue monitoring on day 8 and as needed until therapeutic 4
- Once INR reaches ≥2.0, confirm it remains ≥2.0 for 24 hours before stopping enoxaparin 1
Common Pitfalls to Avoid
Do not stop enoxaparin after only 5 days if INR is subtherapeutic - both the time requirement AND the INR requirement must be satisfied 1. Many clinicians mistakenly discontinue enoxaparin after exactly 5 days regardless of INR, which leaves patients inadequately anticoagulated.
Do not use the edoxaban transition protocol - unlike warfarin, edoxaban should NOT be administered concurrently with parenteral anticoagulants 1. This is a distinct difference between transitioning to warfarin versus DOACs.
Special Considerations
Renal Impairment
- Exercise caution with enoxaparin if creatinine clearance <30 mL/min due to drug accumulation 1
- Warfarin dosing may need adjustment but is not contraindicated in renal disease 1
Hepatic Disease
- Avoid warfarin in moderate-to-severe liver disease or hepatic coagulopathy 1
- Lower initial warfarin doses are prudent in any degree of liver dysfunction 1
Pregnancy
- Avoid warfarin in pregnant or nursing patients 1
- Enoxaparin can be continued throughout pregnancy if anticoagulation is needed 1
Duration of Anticoagulation
After successful transition, continue warfarin for at least 6 months for venous thromboembolism, with specific duration determined by the underlying indication and risk factors 1.