Some patients require temporary interruption of anticoagulants for surgery or other procedures. The choices based on risk and benefit to the individual are:

• Discontinuation of warfarin 3–5 days before surgery

• Lowering of warfarin dose during the procedure

• Discontinuation of warfarin and treatment with intravenous heparin before and after surgery until warfarin can be resumed

If the INR increases too much, vitamin K, orally or by injection will promote clotting. Side effects of vitamin K are flushing, dizziness, rapid heart rate, low blood pressure, shortness of breath, and sweating. Fresh frozen plasma may also be used to provide those clotting factors needed to reverse the effects of warfarin. When a person has very severe bleeding, concentrated clotting factors II, VII, IX, and X are added.

Treatment for DVT in the arm is the same as for DVT in the leg. For treatment of superficial venous thrombophlebitis, see Chapter 7.