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Date of last update: 10/20/2017.

Forum Name: Clots & Anticoagulants

Question: Tobaccos effect on warfarin sod

 Autumn16 - Tue Mar 25, 2008 3:21 pm

Hello, My ? is ... HOW does tobacco smoking effect Warfarin SOD ?
Does it make it more effective (INR count go up) or
Does it make it less efffective (INR count go down)?

Yes, smoking is risky and certainly not recommended .. BUT, it is REALLY
IMPORTANT for me to know what it does to your INR count.

Thank You

 Dr. A. Madia - Thu Mar 27, 2008 8:27 am

User avatar Hi,

This is an interesting question, have not encountered such a query till now. After reviewing the literature on this I have found some information that might be useful to you.

First the basics: Warfarin is a medicine that prevents clotting. This it does by preventing the synthesis of clotting factors by the liver. Liver uses Vitamin K to produce these clotting factors.

Now, smokeless tobacco apparently contains a lot of Vitamin K. When liver gets extra vit K the effect of Warfarin inhibiting the synthesis of clotting factors is blunted out, and Liver is able to continue production of the clotting factors. Thus warfarin becomes ineffective and patients might develop undesirable clotting in arteries.

So those patients who have been advised to take warfarin because of their disease should absolutely refrain from using smokeless tobacco. ... 7v2?ck=nck
 Autumn16 - Thu Mar 27, 2008 11:04 am

Thank you Dr. Madia, I appreciate it.
However, I already had found the research on Smokeless Tobacco ... What I
am trying to ascertain are the effects of Regular Tobacco Smoking. I have
been unable to get a clear cut answer on whether it lowers or raises your INR
count. Again Thank You and if you have any further information I'd welcome it.
 Dr. A. Madia - Sat Mar 29, 2008 1:03 am

User avatar Hi Autumn 16,

There is no clear cut mention of tobacco smoking on warfarin effect in literature, not that I could find.

Vit K is heat stable that is to say it is not destroyed by normal cooking. So dietary sources are good for Vit K even when cooked. However my common sense and logic says thet Vit K in tobacco is unlikely to survive burning as in the cigarette. Also I do not know that If at all it survives incineration whether it can get absorbed via the smoke through the mucus membranes.


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