Guidelines for Managing Patients Receiving Anticoagulant Therapy

We all treat patients who are taking the vitamin K antagonist Warfarin (coumadin). It only takes one bad experience with a patient on Warfarin for a dentist to respect this drug. I often tell the story of a resident colleague of mine who decided to give a patient who was on high levels of Warfarin an inferior alveolar nerve block for pain. The patient bled so much from the needle puncture wound that he required hospital admission and blood transfusion! While such an incident is fortunately rare, the respect with which we treat a patient on Warfarin should be universal.

There has been some discussion in both the medical and dental literature lately which suggest that we no longer need to be as concerned about the bleeding risk of patients on Warfarin. These authors believe that the risk of medical complication such as stroke is much greater than bleeding risk. They also believe that most oral bleeding can easily be controlled with local measures. This may be true in most cases, but I can assure you that the risk of bleeding is very real, not to mention the risk associated with banked blood products. I would like to share with you my personal protocol for managing the patient on Warfarin.

  1. Assess the patient to determine the extent of required surgery and bleeding potential.
  2. Consult with the Patient’s physician:
  • Why are they on Warfarin?
  • What are their most recent Prothrombin Time (PT) & International Normalization Rate (INR) values and when were they obtained.
  • Can the patient withdraw Warfarin therapy and what is the medical risk to the patient.
  1. Obtain the PT and INR values.
  2. If the physician agrees to permit withdrawing Warfarin,use these guidelines:
  • Warfarin has a half-life of about 36 hours so it takes 48 – 72 hours for PT & INR to return to normal.
  • Most simple surgical procedures can be accomplished with a PT of 1.5 times control (18 or under) and INR levels of 2.5. Local measures such as suturing, gelfoam, surgicel,etc. must be accomplished if the PT or INR is above normal.
  • The patient can resume Warfarin when bleeding is controlled.
  • The patient should return to their physician 1 week after surgery for new PT & INR levels.

Remember, the dentist and the medical doctor must communicate to determine the risk/benefit level for each situation and the patient must also be informed of such risks. The dentist is not qualified to predict the medical risk of withdrawing Warfarin and the medical doctor is not qualified to predict the bleeding risk of the proposed dental procedure. The medical doctor will not be the one managing the bleeding should it be uncontrollable with local measures, so don’t let the medical doctor force you into a situation that makes you uncomfortable.

If the PT & INR are very high and the medical doctor does not consent to withdrawing or decreasing Warfarin to a surgical acceptable level, the patient can be placed in the hospital, the Warfarin stopped, and heparin started. Heparin stops working in about 3 hours so the medical risk is greatly decreased. Unfortunately, most patients will not be happy with this protocol as Medicare will not pay for the hospital expenses for such services and the patient will have to pay the hospital bill “out of pocket.”

Hopefully, this has given you some insight to this complex issue. If you find anything helpful from this article let it be this: Never, under any circumstances, tell a patient to stop Warfarin without consulting with their medical doctor and documenting this in the patient’s chart.


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