• Risk Factors
• Therapeutic Ranges
• Loading Dose
• Duration of Treatment
• Warfarin Overdose
• Drug Interactions
• Surgery
• Alternative Loading Protocol

Peri-operative warfarin management

1. Assess risk of bleeding. Find out more
2. Assess risk of thrombosis. Find out more
3. Low risk management protocol. Find out more
4. High risk management protocol. Find out more

General Comments

In any individual patient it is important to consider the benefits vs risks of any approach.

Differences in approach to anticoagulant management pre- and postoperatively relates to the fact that surgery is an important risk factor for venous, but not arterial thromboembolism.

• Warfarin is a medication with a narrow therapeutic index. Stopping before an elective operation/procedure and restarting again is ideally done with close monitoring of the INR in a planned, organised way.
• If the therapeutic INR is in the range 2-3 it usually takes about 4 days for the INR to fall to 1.5 or less in most patients.
• At INR < 1.5, most surgery and procedures can be safely performed. It is important to discuss the acceptable INR with the surgeon/proceduralist involved, as there is variation from case to case.
• After restarting warfarin it usually takes 3 days for the INR to reach > 2.0
• Not all patients on warfarin need Bridging Anticoagulation. Careful consideration is required to decide if a patient needs Bridging Anticoagulation with heparin (either Low Molecular Weight Heparin such as Enoxaparin/Clexane or IV heparin).