Can Lovenox (enoxaparin) be used to bridge warfarin when the international normalized ratio (INR) goal is changed to 3.0-4.0?

From the Guidelines

Yes, Lovenox (enoxaparin) can be used to bridge warfarin therapy when changing the INR goal to a higher range of 3.0-4.0, as recommended by the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation 1. The bridging process typically involves continuing your current warfarin dose while adding Lovenox injections until your INR reaches the new target range. For most adults, Lovenox is dosed at 1 mg/kg subcutaneously twice daily or 1.5 mg/kg once daily, as stated in the management of anticoagulated patients who require surgery or other invasive procedures 1. You should continue the Lovenox injections until your INR has been in the new target range (3.0-4.0) for at least two consecutive days. This bridging approach is necessary because warfarin takes several days to reach therapeutic effect, and during the transition to a higher INR target, you may be at increased risk of thrombosis. The higher INR target of 3.0-4.0 is typically used for specific conditions like mechanical heart valves or recurrent thrombosis despite therapeutic anticoagulation. Some key points to consider when bridging warfarin therapy with Lovenox include:

• The risk of thromboembolism and bleeding should be balanced when deciding on bridging therapy 1
• The CHA2DS2-VASc score can be used to assess stroke risk in patients with nonvalvular AF 1
• The INR should be determined at least weekly during initiation of antithrombotic therapy and at least monthly when anticoagulation (INR in range) is stable 1 Be aware that this higher INR range also carries an increased bleeding risk, so close monitoring is essential. You should have your INR checked frequently during this transition period, typically every 2-3 days until stable in the new range. It is also important to note that the use of Lovenox injection is not recommended for thromboprophylaxis in patients with prosthetic heart valves, as stated in the FDA and Aventis warning 1.

From the Research

Bridging Warfarin with Lovenox

• The use of Lovenox (enoxaparin) to bridge warfarin therapy is a common practice, especially when the international normalized ratio (INR) goal needs to be adjusted 2.
• In patients with deep vein thrombosis (DVT), enoxaparin can be used as a bridge to warfarin until the INR reaches the desired range 2.
• The study by 2 showed that once-daily enoxaparin plus warfarin was effective and safe for the outpatient ambulatory treatment of lower-limb DVT.
• However, the decision to use enoxaparin to bridge warfarin should be based on individual patient factors, such as renal function and bleeding risk 3, 4.

Adjusting INR Goal to 3.0-4.0

• The INR goal of 3.0-4.0 is higher than the typical range of 2.0-3.0 recommended for most patients on warfarin therapy 5.
• A higher INR goal may be indicated for certain clinical conditions, such as mechanical heart valves or recurrent venous thromboembolism 5.
• However, a higher INR goal also increases the risk of bleeding, and patients should be closely monitored for signs of bleeding 5, 3.

Safety and Efficacy of Enoxaparin

• Enoxaparin has been shown to be effective in preventing venous thromboembolism (VTE) in patients with renal impairment 4.
• However, enoxaparin may increase the risk of major bleeding in patients with renal impairment, especially in those with severe renal dysfunction 3.
• The study by 2 showed that enoxaparin plus warfarin was safe and effective for the treatment of DVT, with a low risk of major bleeding.