Pharmacology Post: Warfarin

Also known as Coumadin, warfarin is a prothrombin synthesis inhibitor that can be used as a preventive or to treat various conditions. Warfarin is an anticoagulant, and the major adverse effect of anticoagulants is excessive bleeding. This is especially important for dental treatments that involve the manipulation of gingival tissue.

What is warfarin used for?

Warfarin can be used as a preventive for those patients who have had deep venous thrombosis or thromboembolic agents such as unstable angina or myocardial infarctions.

Warfarin can also be used to treat for immediate anticoagulation in the event of a deep venous thromboembolism.

Image result for deep venous thrombosis

What are the side effects of warfarin?

Birth defects are a major adverse effect of warfarin, as it can easily cross the placenta and cause fetal hemorrhagic disorder, as well as fetal abnormal bone formation. Because of these side effects, warfarin is a Category X drug and is contraindicated in those patients who are pregnant.

Should we work on patients who are using warfarin?

Absolutely, but only under certain parameters. Patients who take warfarin should be instructed NOT to stop medication before receiving dental care. An INR reading that is recent (30 days) should be within the therapeutic range of 2.0-4.0. Any INR reading above 4.0 should be avoided. Local hemostatic measures for procedures that may induce bleeding should also be utilized during treatment in case an emergency occurs (gauze, gelatin sponges, sutures). In the event that the effects of warfarin need to be reversed, Vitamin K is the reversal agent of choice.

To Summarize:

  • Warfarin is an anticoagulant that is primarily used as a preventive measure for those who have deep venous thrombosis or other thromboembolitic events
  • Warfarin can cause excessive bleeding in patients
  • Warfarin should NOT be used by pregnant patients
  • Warfarin is O.K. to use before dental therapy so long as the INR is recent and in an acceptable range (2.0-4.0)


(n.d) Antithrombotic Agents. Dr. Yingzi Chang. A.T. Still Missouri School of Dentistry and Oral Health.

2018. Parameters of Care. Dr. Charles Fuszner. A.T. Still Missouri School of Dentistry and Oral Health.

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