INR change with weight change

[MartinF]

Two years ago I dropped about 10 lbs from 184 to 175 and my INR lowered. My warfarin was adjusted and it was brought back into range.
In the past year I've lost another 15 lbs, down to around 160 lbs. And my recent INR was lower again.
Has anyone else had this reaction?
I'm also under high stress but I don't think that's involved.
Martin

 

[pellicle]

personally I find high stress more of a predictor than how much I weigh.

as always, don't attempt to second guess the why, just push that to the side of the plate and go for the main meal of "correct dose for attaining the INR you need"

intention to dose is only INR

 

[Unicusp]

personally I find high stress more of a predictor than how much I weigh.

as always, don't attempt to second guess the why, just push that to the side of the plate and go for the main meal of "correct dose for attaining the INR you need"

intention to dose is only INR

Question on Warfarin and INR. Do you find that one can slowly build a tolerance to Warfarin and must increase dosage over time to maintain INR? Or does it take awhile for one to adapt and stabilize?
I'm almost at the one year mark and find that recently I've had to increase overall weekly dosage by 10% to maintain target INR of 2.5. Diet, exercise, weight, stress etc have all been stable and consistent.

 

[pellicle]

Question on Warfarin and INR. Do you find that one can slowly build a tolerance to Warfarin and must increase dosage over time to maintain INR? Or does it take awhile for one to adapt and stabilize?

I understand that feeling and when I first commenced warfarin I wonderd if I was experiencing that. The answer however is this

https://pubmed.ncbi.nlm.nih.gov/19336266/
Results: A steady increase in warfarin requirements was seen over the three months in patients with mechanical valves, bioprosthetic valves or valve repairs. The mean dose of warfarin increased by 26% while the mean INR decreased from 2.5 to 2.1. In contrast, both the mean dose of warfarin and the INR were stable in controls. TTR in patients after valve surgery was 48.5%, with 40.8% of time spent at an INR below 2.0. A dosing algorithm was modeled from the data in this patient group.

This may also be worth a read:
https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC6287325/
Basically the answer is "dose as INR dictates"

HTH


Best Wishes

 

[Unicusp]

I understand that feeling and when I first commenced warfarin I wonderd if I was experiencing that. The answer however is this

https://pubmed.ncbi.nlm.nih.gov/19336266/
Results: A steady increase in warfarin requirements was seen over the three months in patients with mechanical valves, bioprosthetic valves or valve repairs. The mean dose of warfarin increased by 26% while the mean INR decreased from 2.5 to 2.1. In contrast, both the mean dose of warfarin and the INR were stable in controls. TTR in patients after valve surgery was 48.5%, with 40.8% of time spent at an INR below 2.0. A dosing algorithm was modeled from the data in this patient group.

This may also be worth a read:
https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC6287325/
Basically the answer is "dose as INR dictates"

HTH


Best Wishes

Interesting. Thanks for the information. Good reads. I see dosage is correlated to weight as well, where higher weight is usually higher dosage. But my earlier thought was related to seeing what some people on here take as weekly doses (49mg) who have been on Warfarin a long time, vs me currently at 26mg with less than 1 year use. I am leaner then avg at about 170lbs. at 6' tall, so that may partially explain the lower dosage.

 

[dick0236]

Question on Warfarin and INR. Do you find that one can slowly build a tolerance to Warfarin and must increase dosage over time to maintain INR? Or does it take awhile for one to adapt and stabilize?

I have found my need for warfarin to decrease with age and activity level. In my 30s-50s I took 7.5/10 mg warfarin per day to maintain an INR of 2.5-3.5. After I retired in my early 60s my need for warfarin has decreased to a steady 5mg/per day for the past +/- 20 years. IMO I believe my need for warfarin has declined along with my working activity and the change in personal habits and lifestyle.

 

[pellicle]

But my earlier thought was related to seeing what some people on here take as weekly doses (49mg

I often wonder why Americans love talking about their daily dose as weekly doses, I have a personal theory that it's because since they can't be different and use ounces (being forced to use SI units like milligrams) they feel a need to be different and use weekly instead of daily so that the rest of us have to divide by something just to understand what they mean.

Anyway its interesting that you picked up on the body weight correlation, but I think you'll find that the genetic correlation is far more significant. Meaning that you may find a small variation as your weight changes, but the genetic differences between people (the observed 7mg per day vs your ~ 3.7mg per day) can result in people taking more than 10 times the dose of others.

https://www.ncbi.nlm.nih.gov/books/n/gtrbook/warfarin/bin/20160608warfarin.pdf
ultimately this is all academic as in the vast majority of cases (I would say 99.999% of them) no pre genetic testing is done and dose is done by starting low (like 4mg) and titrating up. Then once on a so called "stable dose" the patient then adjusts dose (or doesn't) based on actual empirical (hopefully weekly) measurements (INR).



Best Wishes

 

[Superman]

I don’t think it’s an American thing. It’s just easier for me to say 42mg a week that give the daily rundown. Especially with folks splitting pills or taking one less mg on Tuesday’s during a full moon or whatever. It’s also easier to consider the overall dosing change when it’s often just one or two mg’s a week to get back in range.

 

[Superman]

Two years ago I dropped about 10 lbs from 184 to 175 and my INR lowered. My warfarin was adjusted and it was brought back into range.
In the past year I've lost another 15 lbs, down to around 160 lbs. And my recent INR was lower again.
Has anyone else had this reaction?
I'm also under high stress but I don't think that's involved.
Martin

I think it’s more metabolism change than a simple weight change. That’s why you may need a higher dose when you lose weight than when you’re heavier. You metabolize it quicker.

But I’m just spitballing.

 

[pellicle]

I don’t think it’s an American thing.

I don't seem to see it used anywhere else. I note that in this article (which I didn't post because although I read it it brought nothing to the table) in the above referenced journal every single contributing author was from the USA.

https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC3361510/
Contributor Information
Andrea H Ramirez, Department of Medicine, Vanderbilt University in Nashville, TN, USA.

Yaping Shi, Department of Biostatistics, Vanderbilt University in Nashville, TN, USA.

Jonathan S Schildcrout, Department of Biostatistics, Vanderbilt University in Nashville, TN, USA.

Jessica T Delaney, Department of Medicine, Vanderbilt University in Nashville, TN, USA.

Hua Xu, Department of Biomedical Informatics, Vanderbilt University in Nashville, TN, USA.

Matthew T Oetjens, Center for Human Genetics Research, Vanderbilt University in Nashville, TN, USA.

Rebecca L Zuvich, Center for Human Genetics Research, Vanderbilt University in Nashville, TN, USA.

Melissa A Basford, Office of Research, Vanderbilt University in Nashville, TN, USA.

Erica Bowton, Office of Research, Vanderbilt University in Nashville, TN, USA.

Min Jiang, Department of Biomedical Informatics, Vanderbilt University in Nashville, TN, USA.

Peter Speltz, Department of Biomedical Informatics, Vanderbilt University in Nashville, TN, USA.

Raquel Zink, Department of Biomedical Informatics, Vanderbilt University in Nashville, TN, USA.

James Cowan, Institute for Clinical & Translational Research, Vanderbilt University in Nashville, TN, USA.

Jill M Pulley, Medical Administration, Vanderbilt University in Nashville, TN, USA.

Marylyn D Ritchie, Department of Biomedical Informatics, Vanderbilt University in Nashville, TN, USA and Center for Human Genetics Research, Vanderbilt University in Nashville, TN, USA and Department of Molecular Physiology & Biophysics, Vanderbilt University in Nashville, TN, USA.

Daniel R Masys, Department of Biomedical Informatics, Vanderbilt University in Nashville, TN, USA.

Dan M Roden, Department of Medicine, Vanderbilt University in Nashville, TN, USA and Department of Pharmacology, Vanderbilt University in Nashville, TN, USA.

Dana C Crawford, Center for Human Genetics Research, Vanderbilt University in Nashville, TN, USA and Department of Molecular Physiology & Biophysics, Vanderbilt University in Nashville, TN, USA.

Joshua C Denny, Department of Medicine, Vanderbilt University in Nashville, TN, USA and Department of Biomedical Informatics, Vanderbilt University in Nashville, TN, USA and Eskind Biomedical Library, Room 448, 2209 Garland Ave, Nashville, TN 37232, USA.




but we (you and I) have been down this path before (and that's ok with me ;- )

 

[pellicle]

. It’s just easier for me to say 42mg a week that give the daily rundown. Especially with folks splitting pills or taking one less mg on Tuesday’s during a full moon or whatever.

well as I've said before I believe it brings nothing but redundant complexity to the table (perhaps making it seem more mysterious and thus cementing in the importance of the clinic).

• your pills are labelled in mg
• you (hopefully) take the pills every day
• seeing the pills you take can help you counter errors in distribution ("say, aren't I supposed to be on 7mg?, this is 5")
• the weekly dose has to be somehow divided down for daily distribution, which may not make clear why 5mg and 10mg is not ideal (just because you have 5mg tablets)

 

[Superman]

well as I've said before I believe it brings nothing but redundant complexity to the table (perhaps making it seem more mysterious and thus cementing in the importance of the clinic).

• your pills are labelled in mg
• you (hopefully) take the pills every day
• seeing the pills you take can help you counter errors in distribution ("say, aren't I supposed to be on 7mg?, this is 5")
• the weekly dose has to be somehow divided down for daily distribution, which may not make clear why 5mg and 10mg is not ideal (just because you have 5mg tablets)

View attachment 888369

I know all the detail for me. That’s fine. When I talk in here, I don’t need to lay out my daily dosing minutia. It saves a couple sentences. I also don’t like a wide variance in daily dosing either. But I’ve been a pretty rock steady 6mg daily for a long time. Occasionally I need to throw a day or two at 5 mg’s.

BTW, I don’t need to change your mind. You do you. Doesn’t matter to me one bit, unless someone is struggling to stay in range. Then different ways of thinking might be helpful for them.

 

[pellicle]

BTW, I don’t need to change your mind. You do you

I didn't request you change your mind. If >I do< then please give me a clear reason (or reasons)

As far as people struggling to maintain a dose / INR relationship I do indeed work with that with some significant success. Often the reasons boil down to those weird weekly dose algorithms clinics come up with.

Again, it doesn't bother me what people do and if you have a 'gut feel' heuristic that woks for you then that's excellent, its just when it comes to helping others those are often difficult without getting into the "minutia"

 

[pellicle]

BTW

oh, and I feel its worth mentioning to you (I happen to care more about you than the casual readership) that I was brought up discussing things. It was what I did at school in public speaking and debating (which is always dispassionate) and what I did in science when you have to defend a proposition.

My perspective is that arguments are discussion points or parts of a formula that are subject to change. Sadly the common meaning of an argument is (something like) "a heated exchange involving difference of opinion and rooted in an unwillingness to change"

I'm always willing to change my view if presented with evidence that shows why I would benefit from that. If I wasn't then my engagement would be disingenuous.

Best Wishes

 

[Superman]

I'm always willing to change my view if presented with evidence that shows why I would benefit from that. If I wasn't then my engagement would be disingenuous.

Best Wishes

All good. Frankly I just don’t see this as something worth trying to convince anyone of. Your take is correct when looking at details. My 42mg’s a week amounts to posting style more than dosing style. And I really rarely talk dosing anyway. I certainly don’t help people with their dosing other than to encourage them to take an active rather than a passive roll with their medical team and their dosing.

 

[pellicle]

Frankly I just don’t see this as something worth trying to convince anyone of.

unless they are having trouble ... if no trouble, then keep doing what works

its a bit like the metric system vs the inch,foot,yard or ounce, pound, stone thing. If its just a number then it doesn't matter, but if you have to do maths with it its a nightmare.

https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC2722908/"their model"

This strong performance of ordinary least-squares regression was fortuitous because it yielded a simpler and more easily understood model than many of the more complex modeling approaches we used. Because the resulting dose algorithm computes the square root of the weekly dose, the output must be squared to compute the weekly dose.​

 

[Unicusp]

Dosing: I summarized it as weekly dosing because daily can get more complex and add nothing to the conclusion. For example, until recently I was on a steady 3mg/day. Simple yes. But now on alternating days (4 of them) I increased to 3.5mg/day with 3mg/day for the other 3 days.
Before the 3mg/day routine (which was brief), I was on 2.5mg/ day for 3 days per week, and 3mg/day for 4 days per week, all alternating.
I concur that as I increase my activity level by increasing duration and intensity of workouts, could be a contributing factor. But, oddly I've recently gained around 4 lbs. which has been near impossible to do in my lifetime. So, then I wonder if Warfarin somehow does mess with metabolism or it's unrelated.
Blood pressure, oxygen level, heart rate all very good but my heart rate has gotten very high (198 just yesterday) during weight training (according to my dumb watch). No pain or symptoms to indicate it was high other than the reading. So, I'm trying to be more careful and not "blow" anything. Tough, because I feel great and can lift way more than I am doing. Doing more endurance and high rep strength training, not crazy heavy weights. I'm no Arnold!

 

[pellicle]

So, then I wonder if Warfarin somehow does mess with metabolism or it's unrelated.

been there, done that. Spent over 2 years wearing a Garmin and used its measurement of energy (included all training using my HR monitor) and found a very poor correlation coefficient. Every avenue I've checked out fails to hold up over time.

I still maintain the low hanging fruit is measure your INR, if its not in need of dose adjustment then don't. Only adjust on trends (spanning weeks).

If you find a simpler thing please do post it (and your data)

 

[carolinemc]

Question on Warfarin and INR. Do you find that one can slowly build a tolerance to Warfarin and must increase dosage over time to maintain INR? Or does it take awhile for one to adapt and stabilize?
I'm almost at the one year mark and find that recently I've had to increase overall weekly dosage by 10% to maintain target INR of 2.5. Diet, exercise, weight, stress etc have all been stable and consistent.

Nope, it is that the more active you are and the food changes, and medications, it can make you have to increase the INR. If you are under a great deal of stress on the job, or at home, you will have to adjust the Warfarin. The only intolerance to warfarin is becoming allergic to it and have to find a different blood thinner to use instead. Ask your tester about Warfarin and the dosages and what makes you have to increase or decrease the dosage. Good luck in getting educated. We have all been there, those that are on warfarin

 

[tom in MO]

Question on Warfarin and INR. Do you find that one can slowly build a tolerance to Warfarin and must increase dosage over time to maintain INR? Or does it take awhile for one to adapt and stabilize?
I'm almost at the one year mark and find that recently I've had to increase overall weekly dosage by 10% to maintain target INR of 2.5. Diet, exercise, weight, stress etc have all been stable and consistent.

Question on Warfarin and INR. Do you find that one can slowly build a tolerance to Warfarin and must increase dosage over time to maintain INR? Or does it take awhile for one to adapt and stabilize? No you don't build up a tolerance like one does to pain killers. It takes awhile after surgery for your body to return to a stable state after any open heart surgery. After that, I find that my INR+dose changes for unknown reasons. I've tried to link it to gross diet (more greens in summer or less exercise in winter) but cannot correlate anything. I rarely need to adjust my basic daily dose but never by much.

Weekly vs. daily dose is a matter of perspective. Thinking of it on a daily basis gives a person the mistaken feeling that a change in daily dose should bring a change in INR the next day. In reality it takes a few days, thus some use a weekly dose.