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Protocol: Starting Coumadin in elderly inpatients
1. General
  1. Safe (no patient had an INR >4)
  2. Therapeutic INR achieved within 6-7 days
2. Initial Dose: 4 mg daily for first 3 days
3. Dosing protocol after day 3 based on daily INR
  1. INR <1.3: Warfarin 5 mg
  2. INR 1.3-1.4: Warfarin 4 mg
  3. INR 1.5-1.6: Warfarin 3 mg
  4. INR 1.7-1.8: Warfarin 2 mg
  5. INR 1.9-2.4: Warfarin 1 mg
  6. INR >2.4: Hold Warfarin, check INR daily
4. References
  1. Siguret (2005) Am J Med 118:137
Protocol: Starting Coumadin in general patients
1. Pointers
  1. Loading Warfarin dose is not needed
2. Indications for starting with concurrent Heparin
  1. Thrombophilic state (e.g. known Protein C Deficiency)
  2. Thromboembolism
3. Indications for starting Warfarin without Heparin
  1. Chronic stable Atrial Fibrillation
4. Starting dose of Warfarin
  1. Usual: 5 mg PO qd (anticipate therapeutic by day 4-5)
  2. High Dose: 7.5 to 10 mg qd
    1. If urgency to reach therapeutic level
    2. Study: 10 mg start was therapeutic 1.4 days earlier
      1. Kovacs (2003) Ann Intern Med 138:714-9
  3. Low dose: 2.5 mg PO qd
    1. Elderly
    2. Liver disease
    3. High risk of bleeding
5. Protocol
  1. Monitor daily ProTime with INR
  2. Stop Heparin when 2 consecutive INRs therapeutic
  3. Monitor INR 2-3 times per week for 1-2 weeks
  4. Monitor INR every 2-4 weeks when stable
6. INR 2.2 to 2.3 associated with lowest overall mortality
  1. Oden (2002) BMJ 325:1073-5
Protocol: Adjust Coumadin (based on INR 2 to 3)
1. See Coumadin for other target INR indications
2. INR less than 2
  1. Increase weekly Coumadin dose by 5 to 20%
3. INR 3 to 3.5
  1. Decrease weekly Coumadin dose by 5 to 15% or
  2. Maintain same dose and recheck in 7 days
    1. Banet (2003) Chest 123:499-503
4. INR 3.6 to 5.0
  1. Consider withholding one Coumadin dose
  2. Decrease weekly Coumadin dose by 10 to 15%
5. INR 5.0 to 10.0
  1. Withhold 1 to 2 Coumadin doses
  2. Decrease weekly Coumadin dose by 10 to 20%
  3. Indications for Vitamin K
    1. Risk of bleeding: Vitamin K 1 to 2.5 mg PO x1 dose
    2. Surgery in 24 hours: Vitamin K 2 to 4 mg PO x1 dose
6. INR exceeds 10.0
  1. Hold Warfarin
  2. Vitamin K 3 to 5 mg PO x1 dose
  3. Monitor INR daily and consider repeating Vitamin K
  4. Anticipate significantly lower INR within 24-48 hours
7. Serious or Life-threatening bleeding (esp. INR >20)
  1. Replace Clotting Factors
    1. Vitamin K 10 mg by slow IV infusion
    2. Fresh Frozen Plasma (FFP) 15 ml/kg
    3. Prothrombin Complex Concentrate (PCC) 50 U/kg
  2. Recheck INR at 6 hour intervals
    1. Consider repeating Vitamin K at 12 hours
Dosing Adjustment: Decreased Dosing
1. Decrease Dosing by 20% (27.5 mg per week)
  1. Coumadin 2.5 mg PO on Monday, Wednesday, Friday
  2. Coumadin 5 mg PO all other days
2. Decrease Dosing by 15% (30 mg per week)
  1. Coumadin 2.5 mg PO on Monday and Friday
  2. Coumadin 5 mg PO all other days
3. Decrease Dosing by 5% (32.5 mg per week)
  1. Coumadin 2.5 mg PO on Monday
  2. Coumadin 5 mg PO all other days
Dosing Adjustments: Standard Dosing
1. Coumadin 5 mg PO qd (35 mg per week)
Dosing Adjustments: Increased Dosing
1. Increase Dosing by 5% (37.5 mg per week)
  1. Coumadin 7.5 mg PO on Monday
  2. Coumadin 5 mg PO all other days
2. Increase Dosing by 15% (40 mg per week)
  1. Coumadin 7.5 mg PO on Monday and Friday
  2. Coumadin 5 mg PO all other days
3. Increase Dosing by 20% (42.5 mg per week)
  1. Coumadin 7.5 mg PO on Monday, Wednesday, Friday
  2. Coumadin 5 mg PO all other days
Resources
1. Point of Care Guide by Mark Ebell, MD
  1. http://www.aafp.org/20050515/pocform.html
References