# Drug of the Week Series - 19.1

**URL:** <https://www.medboundhub.com/t/drug-of-the-week-series-19-1/22856>\
**Category:** General\
**Created:** [August 25, 2026, 3:08am UTC](https://www.medboundhub.com/t/drug-of-the-week-series-19-1/22856 "2026-08-25T03:08:48Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![SanmeetKour](https://yyz1.discourse-cdn.com/flex033/user_avatar/www.medboundhub.com/sanmeetkour/32/5452_2.png) [@SanmeetKour](https://www.medboundhub.com/u/SanmeetKour)\
**Post date:** [August 25, 2026, 3:08am UTC](https://www.medboundhub.com/t/drug-of-the-week-series-19-1/22856/1 "2026-08-25T03:08:48Z")

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Scenario:  
A 58-year-old man with a mechanical heart valve has been taking warfarin regularly. During a routine follow-up, his **INR is found to be 5.8**. He also reports mild gum bleeding.

Poll:  
What is the most likely explanation for this patient’s increased bleeding risk?

_Poll ([view on site](https://www.medboundhub.com/t/drug-of-the-week-series-19-1/22856/1))_

**Question:  
Why does warfarin require regular INR monitoring, and what is the significance of vitamin K in its mechanism of action?**

MBH/PS

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**Author:** ![Dr.Neha\_laskar](https://yyz1.discourse-cdn.com/flex033/user_avatar/www.medboundhub.com/dr.neha_laskar/32/5770_2.png) [@Dr.Neha\_laskar](https://www.medboundhub.com/u/Dr.Neha_laskar)\
**Post date:** [August 25, 2026, 5:30am UTC](https://www.medboundhub.com/t/drug-of-the-week-series-19-1/22856/2 "2026-08-25T05:30:00Z")

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Warfarin requires regular INR monitoring because its therapeutic window is narrow, and its effect can vary with diet, medications, and liver function.INR monitoring ensures adequate anticoagulation.

Warfarin blocks vitamin K recycling and causes prolonged PT/INR

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<div class="post-metadata">

**Author:** ![Vaishnavi\_13](https://yyz1.discourse-cdn.com/flex033/user_avatar/www.medboundhub.com/vaishnavi_13/32/5780_2.png) [@Vaishnavi\_13](https://www.medboundhub.com/u/Vaishnavi_13)\
**Post date:** [August 25, 2026, 6:03am UTC](https://www.medboundhub.com/t/drug-of-the-week-series-19-1/22856/3 "2026-08-25T06:03:36Z")

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Warfarin requires regular INR monitoring to maintain the desired level of anticoagulation and avoid excessive bleeding or clot formation. It works by inhibiting vitamin K recycling, which reduces the production of vitamin K–dependent clotting factors II, VII, IX, and X.