What to do for a patient with subtherapeutic anticoagulation on Clexane (enoxaparin)?

Management of Subtherapeutic INR with Enoxaparin

For a patient with INR 1.6 (target range 2.5-3.0) who is already on enoxaparin 40mg daily, the recommended approach is to continue enoxaparin at the current dose while increasing the vitamin K antagonist (VKA) dose to achieve therapeutic INR, rather than adjusting the enoxaparin dose.

Assessment of Current Situation

• Current status: INR 1.6 (subtherapeutic) with target range of 2.5-3.0
• Current bridging therapy: Enoxaparin 40mg daily
• Clinical concern: Inadequate anticoagulation with increased thrombotic risk

Management Algorithm

Step 1: Continue Current Enoxaparin

• Maintain enoxaparin 40mg daily as bridging therapy
• Do not discontinue enoxaparin until INR reaches therapeutic range (2.5-3.0) 1
• Enoxaparin provides immediate anticoagulation while waiting for VKA effect

Step 2: Adjust VKA Dosing

• Increase VKA dose to achieve target INR of 2.5-3.0
• Do not use a loading dose of VKA as this increases bleeding risk without faster therapeutic effect 1
• Schedule INR recheck in 3-5 days

Step 3: Monitor Until Therapeutic

• Continue combined therapy (enoxaparin + VKA) until INR is therapeutic for at least 2 consecutive days 1
• Once INR is ≥2.5 for two consecutive readings, discontinue enoxaparin
• Continue VKA therapy at the adjusted dose

Special Considerations

For High Thrombotic Risk Patients

• If patient has mechanical heart valve: Continue enoxaparin 40mg daily until INR is therapeutic 1
• If patient has recent thromboembolism (<3 months): Consider increasing enoxaparin to therapeutic dose (1mg/kg twice daily) until INR is therapeutic 1

For Patients with Renal Dysfunction

• For CrCl <30 mL/min: Do not increase enoxaparin dose; consider switching to unfractionated heparin 1
• Anti-factor Xa monitoring is not recommended for dose adjustment in renal dysfunction 1

Important Caveats

• Do not adjust enoxaparin dose based on INR values, as INR only reflects VKA activity, not LMWH activity
• Do not discontinue enoxaparin prematurely, as this increases thrombotic risk while INR is subtherapeutic
• Avoid administering vitamin K for subtherapeutic INR as this will further delay achieving therapeutic anticoagulation
• If the patient has bleeding risk factors, more cautious VKA dose adjustment may be warranted

Follow-up Plan

• Recheck INR in 3-5 days after VKA dose adjustment
• Continue this approach until therapeutic INR is achieved
• Once stable on VKA therapy alone, schedule regular INR monitoring according to clinical stability

This approach ensures continuous anticoagulation coverage while transitioning to therapeutic oral anticoagulation, minimizing both thrombotic and bleeding risks.