Do you stop heparin when starting Plavix (clopidogrel) for Deep Vein Thrombosis (DVT) prophylaxis?

Management of Heparin When Starting Plavix for DVT Prophylaxis

When starting Plavix (clopidogrel) for DVT prophylaxis, you should stop heparin after an appropriate overlap period of 5 days and once the patient has reached therapeutic anticoagulation with Plavix.

Anticoagulation Transition Protocol

The management of transitioning from heparin to Plavix requires careful consideration of the patient's thrombotic and bleeding risks. Based on current guidelines, the following approach is recommended:

Initial Anticoagulation with Heparin

• Patients requiring DVT prophylaxis typically start with either:
  • Intravenous unfractionated heparin (UFH)
  • Low molecular weight heparin (LMWH) such as enoxaparin
  • Fondaparinux (in selected cases)

Transition to Plavix

1. Overlap Period:

   • Continue heparin for at least 5 days after starting Plavix 1
   • This overlap ensures adequate anticoagulation during the time Plavix takes to reach full antiplatelet effect

2. Monitoring During Transition:

   • For patients on UFH: Monitor aPTT to maintain therapeutic range (1.5-2.5 times control)
   • For patients on LMWH: Routine monitoring not required except in special populations (severe renal impairment, pregnancy) 1

3. When to Discontinue Heparin:

   • Stop heparin after minimum 5-day overlap 1
   • Ensure Plavix has had sufficient time to reach therapeutic effect (typically 5-7 days)

Special Considerations

High-Risk Patients

For patients at high risk of thromboembolism (e.g., recurrent DVT, cancer, thrombophilia):

• Consider longer overlap period
• More careful monitoring during transition
• In patients with multiple risk factors for thromboembolism, heparin should be continued until full anticoagulation with the oral agent is achieved 1

Bleeding Risk Assessment

• Evaluate bleeding risk before transition:
  • Recent bleeding events
  • Platelet count < 50 x 10^9/L
  • Advanced age (≥ 85 years)
  • Severe renal or hepatic failure
  • Concurrent use of other antiplatelet agents 1

Specific Patient Populations

1. Cancer Patients:

   • May require extended LMWH monotherapy (3-6 months) before transitioning to oral agents 1

2. Patients with Heparin-Induced Thrombocytopenia (HIT):

   • Stop heparin immediately
   • Use alternative anticoagulants (e.g., direct thrombin inhibitors) before transitioning to Plavix 1
   • Monitor platelet counts closely

Practical Algorithm

1. Start Plavix at appropriate dose for DVT prophylaxis
2. Continue heparin for minimum of 5 days overlap
3. Monitor for signs of adequate anticoagulation and absence of bleeding
4. Discontinue heparin after minimum 5-day overlap period
5. Continue Plavix for the prescribed duration based on patient risk factors

Common Pitfalls to Avoid

• Premature discontinuation of heparin: Stopping heparin before Plavix reaches therapeutic effect may leave a gap in anticoagulation protection
• Excessive overlap: Prolonged concurrent use of both agents increases bleeding risk unnecessarily
• Failure to monitor: Not monitoring for signs of bleeding or thrombosis during transition period
• Inadequate patient education: Patients should understand the importance of adherence to the prescribed regimen and signs of bleeding to watch for

By following this evidence-based approach, you can safely transition patients from heparin to Plavix for DVT prophylaxis while minimizing both thrombotic and bleeding risks.