Anticoagulation Service For Health Professionals

Guidelines for Management of Patients with INR > 9.0

University of Michigan Anticoagulation Service

  1. Refer patient to the Emergency Room.
  2. Notify patient's primary care physician or Anticoagulation Clinic physician of critical value and patient referral to ER.
  3. Call ER to notify of patient. Suggest administration of vitamin K 5.0-10 mg orally if patient shows no signs of bleeding. (i.e., injectable aqueous vitamin K) are effective when taken orally.
  4. Patients with significant bleeding or a markedly prolonged INR (>20) may require more aggressive treatment (i.e. vitamin K 10mg IV, fresh-frozen plasma, and/or prothrombin complex concentrate). Remind ER personnel that maximum IV infusion rate of vitamin K is 1mg/min. If patient subsequently is discharged from ER, warfarin should be held and INR must be checked the following day. However, the follow-up INR should be approximately 24 hours after receiving vitamin K, since this amount of time is necessary to induce significant coagulation factor synthesis by the liver. Follow-up INR results must be available to the Anticoagulation Clinic within 4 hours of draw. If INR remains greater than or equal to 9 at follow-up, notify the Anticoagulation Clinic physician or patient's primary care physician.
  5. Check INR daily. Resume warfarin when INR is therapeutic. Continue to follow INR daily for several days-i.e. until it enters or is close to (within 1 unit) the therapeutic range. Thereafter, gradually reduce frequency of INR monitoring depending on INR results and clinical situation.
  6. Consider reducing the patient's weekly warfarin dose by 25-30%, unless a cause for the prolonged INR was established and corrected.
  7. May want to consider restarting Coumadin before INR reaches therapeutic range in patient who received vitamin K therapy.

    Note: These general guidelines may need to be modified in selected patients. If questions arise, contact the Anticoagulation Clinic physician (Jim Froehlich, M.D., pager 3936 or Brad Dyke, M.D., pager 4520), the Anticoagulation Clinic nurse (pager 7248, Mon.-Fri. 8AM-5PM), or the cardiology fellow on call.

    Last Reviewed 07/06