**Core Concept:** Warfarin is an anticoagulant medication used to prevent blood clots, such as deep vein thrombosis, pulmonary embolism, and stroke. It works by inhibiting vitamin K-dependent clotting factors, leading to a decrease in prothrombin time and International Normalized Ratio (INR). Before surgery, patients on warfarin require bridging therapy to prevent excessive bleeding during and after surgery.

**Why the Correct Answer is Right:** Warfarin should be stopped 5 days before surgery to achieve a therapeutic INR level and allow for adequate clearance of the drug from the patient's system. This ensures that the patient is not too anticoagulated during surgery, increasing the risk of bleeding, and not too non-anticoagulated, increasing the risk of uncontrolled clot formation.

**Why Each Wrong Option is Incorrect:**

A. 3 days: This is too short a period for warfarin to clear from the patient's system, potentially leading to inadequate anticoagulation during surgery.
B. 7 days: This is too long a period, increasing the risk of clot formation due to prolonged anticoagulation.
C. Different patient-specific factors: The correct duration may vary based on factors like the patient's INR, bleeding risk, and type of surgery. However, the general rule of thumb is 5 days.
D.

**Clinical Pearl:** Adequate warfarin discontinuation duration before surgery is essential for optimal patient safety. In clinical practice, the duration may vary based on individual patient factors, but the common recommendation is to stop warfarin 5 days before surgery to achieve the best balance between bleeding risk and clot formation risk. Patients should be monitored for their INR and adjusted accordingly.

**Correct Answer:** 5 days