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What causes mildly raised INR level despite taking Warfarin?

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Posted on Tue, 13 Dec 2016
Question: I'm on warfarin to was given after I had a heart valve replaced. The testing shows: 4.3, and previous
it was 4.2. The amount of warfarin was 5 mg. I took a 1/2 a tablet the last two days but level hasn't changed.
I'm also taking 1000 mg Vitamin C and an average of 2 Tylenol a day. Anyway I can get the level within
the proper boundary ? Also, how about Praxada ? Got apt with cardiac specialist Friday.
Any ideas ?
doctor
Answered by Dr. Antoneta Zotaj (2 hours later)
Brief Answer:
Stewise approach warfarine dose/INR measurement- please see in detail

Detailed Answer:
Hello,
Thanks for asking at HCM

I carefully read your question and understnad your concern.

We aim to have INR 2-3 in patients with warfarine, in some cases up to 3.5.
In your case you have mildly over the desired level and it would be good to not allow it to go beyond 4.5 or 5.

If you have done a dose change from one tablet a day to 1/2 tablet a day the last 2 days i would recommend you to:
- Continue to take 1/2 tablet a day for another 2-3 days and check the INR regularly. Most of the times the INR will drop in the comming days with the dose reduction you have done
- If the INR does not drop or has the tendency to go up and reaches 4.5 than hold one dose (do not take it for one day)
- Than the next day go on with 1/2 tablet a day and continue to measure INR regularly. Normally at this time INR should have dropped down.
- If you are on a 1/2 tablet a day for 7-10 days and still the INR is above 3.5 than you can try to have 1/2 tablet a day for 3 days and quarter of a tablet for a day. Monitor INR regularly. It should not be under 2.5 and not over 3.5. If lower than 2.5 go back one step and increase the dose backwards.

The risk for bleeding in most patients is low as long as INR is kept under 5 so no need to panic but you need to carefully adjust the doses to help keep INR in the therapeutic levels 2.5-3.5.

If you have signs of bleeding like skin bruises, bleeding gums, dark black stools than you will need to stop warfarine and see a doctor as soon as possible.

Attention: Vitamin C might reduce the effect of warfarine. I would like you to have this in mind in case you are considering to change any doses of it.

Hope this is helpful to you and aswers to your question. In case of any concenrs related to this questions please let me know. Otherwise please close and rate the answer.

Kind regards

Dr Antoneta Zotaj.

Above answer was peer-reviewed by : Dr. Raju A.T
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Answered by
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Dr. Antoneta Zotaj

General & Family Physician

Practicing since :2004

Answered : 4407 Questions

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What causes mildly raised INR level despite taking Warfarin?

Brief Answer: Stewise approach warfarine dose/INR measurement- please see in detail Detailed Answer: Hello, Thanks for asking at HCM I carefully read your question and understnad your concern. We aim to have INR 2-3 in patients with warfarine, in some cases up to 3.5. In your case you have mildly over the desired level and it would be good to not allow it to go beyond 4.5 or 5. If you have done a dose change from one tablet a day to 1/2 tablet a day the last 2 days i would recommend you to: - Continue to take 1/2 tablet a day for another 2-3 days and check the INR regularly. Most of the times the INR will drop in the comming days with the dose reduction you have done - If the INR does not drop or has the tendency to go up and reaches 4.5 than hold one dose (do not take it for one day) - Than the next day go on with 1/2 tablet a day and continue to measure INR regularly. Normally at this time INR should have dropped down. - If you are on a 1/2 tablet a day for 7-10 days and still the INR is above 3.5 than you can try to have 1/2 tablet a day for 3 days and quarter of a tablet for a day. Monitor INR regularly. It should not be under 2.5 and not over 3.5. If lower than 2.5 go back one step and increase the dose backwards. The risk for bleeding in most patients is low as long as INR is kept under 5 so no need to panic but you need to carefully adjust the doses to help keep INR in the therapeutic levels 2.5-3.5. If you have signs of bleeding like skin bruises, bleeding gums, dark black stools than you will need to stop warfarine and see a doctor as soon as possible. Attention: Vitamin C might reduce the effect of warfarine. I would like you to have this in mind in case you are considering to change any doses of it. Hope this is helpful to you and aswers to your question. In case of any concenrs related to this questions please let me know. Otherwise please close and rate the answer. Kind regards Dr Antoneta Zotaj.