Keeping INR in range

The only thing I was told not to eat at all was cranberries, even the pharmicist would tell me not to eat cranberries when prescription was filled.  I was told I could eat anything otherwise but I was not to suddenly change my diet, for instance go on a diet, particularly if I sudden started eating a lot of green salads/vegetables.  I was also told i could drink alcohol but it should not be binge drinking, not that I would lol!  I followed that advice and just made no drastic changes, eating the same amounts of everything week by week and having a few glasses of wine at the weekend and my INR levelled out in the first month and I had to make no changes to my Warfarin medication in the year I took it. 

Vivienne's advice is great and very like what I try to follow.  However t took me four months for my INR to stabilise.  And I was on warfarin for 6 months after my first DVT 28 years ago, and it took nearly the whole of that time to get a consistent reading then too.

I've been told to continue eating green vegetables, but to be consistent and regular in the amount I eat.  I was advised not to cut out these things as they are part of a healthy diet.  The only things I was told to avoid were cranberries, grapefruit and fish oils - it's best to have tuna canned in brine rather than oil, for example.  I got myself of The Coumadine Cookbook which has great tables with the vitamin K content of many foods.  It's an American publication, so some ingredients can't easily be sourced here. However it's a mine of information about a suitable diet.

When I was diagnosed in March, my INR was 1.00 (I can't remember the first time) My daily dose now I've stabilised is 9mg daily, but 10mg on Mondays and Thursdays.  I was on a fairly high dose last time too - I suspect I'm rather resistant to warfarin.  Hopefully it'll stay there now, as I'm on it for life now.

Hi.

INR is a ratio ie a mathematical calculation based on the Prothrombin time (PT) blood result which is measure in seconds.It's the length of time your blood takes to clot in a test tube when they add a reagent which stimulates the blood clotting cascade (process)which usually occurs inside the body.

The normal PT is around 10-15 seconds. If you aren't on warfarin and your blood clotting time is in the normal range then your INR will be 1. Technically they shouldn;t even do the test if you're not on warfarin as the only use of the blood test is for warfarin management, but some Doctors request it when patients have had a DVT becasue they don't really understnad what it's for! If someone's INR is "all over the place" or it takes a long time to get the INR into range at the beginning it's quite often down to the inexperience of the person "dosing" the warfarin. In the beginning If someone is having their INR done every day, and every day that it;s not in range someone increases their warfarin dose then their INR will be all over the place, and by day 5 or 6 will probably suddenly go from 1.8 to 5! Try and remember 72. Any change in the dosage of warfarin will take 72 hours to make a difference to the INR result.

Mary, apart from Cranberry juice, there are no foods that you shouldn't eat whilst on warfarin.

Healthcare providers will tell you to eat a healthy diet whether your on warfarin or not! Eating an unhealthy diet will not affect your INR so there is no reason why a takeaway should affect your INR, unless of course you drink more than your usual amount of alcohol with it!

The only foods that are particularly rich in Vit K are green leafy ones. Other foods might contain Vit K, but not in high enough amounts to affect INR, so you don;t need to worry about how much of those  you eat..If you eat a relatively constant amount of Vit K rich veg then your INR won't be affected.

If, however, you don't usually eat any Vit K rich foods and one day in the week you eat a Vit K rich meal, for example spinach salad , then your INR will be affected.

The key in warfarin therapy is consistent intake, or dose, of Vit K rich foods, alcohol and other medications (including over the counter meds and, importantly,health supplements and herbal remedies.

Quite often people forget about herbal remedies. St Johns Wort , for example can have a drastically increase INR , and can be dangerous if taken with many other medicines and certain foods.

Over the counter medicines that may be taken on an occasional  rather than consistent basis  include Indigestion and heartburn remedies. They may reduce warfarin absorbtion and thus reduce the INR.

I worked in a hospital anticoagulation service for 4 years as a Clinical Nurse Specialist. We managed almost 2000 outpatients and up to 40 inpatients who were on warfarin and the most common reasons for unstable INR's were, in order of importance

Missed or incorrect dose(s) of warfarin taken

Changes in other medications (ie altered dosage or a new medication)

Alcohol intake (usually binge drinking)

Increase in severity of other medical conditions eg Kidney, liver, heart or breathing disorders

Changes in "meal replacement" drinks (ie starting/stopping or changes in the amount)

If your INR has never been stable then it may be one of the above that's affecting it.

Of course, there is a certain skill in "dosing " warfarin, and here in the UK specialist anticoagulation services came about because GPs were only managing a few patients and often didn't have the knowledge or skills to do a good job. At the same time there was an awareness that many people who were on warfarin for stroke prevention (often elderly people with Atrial Fibrillation) were having  TIAs or strokes because their anticoagulation wasn't being managed effectively.

Regarding heparin injections, these are given in the same dose every day. The dose is based on patient weight and doesn't require monitoring. The INR was used to adjust the warfarin dose because at the same time you were having the heparin injections you were also on warfarin. Once the INR reached your therapeutic range (2-3?) then  the heparin injections are no longer required. The heparin injections are used at the beginning of anticoagulation therapy because the first injection works almost immediately to anticoagulate the blood, whereas warfarin takes a while to have an effect and the dose required to get the blood to the required level of anticoagulation varies in individuals.

 

People on warfarin in the UK  might find this site useful.

If you click on the "publications" tab in the top right,the 7th publication down called "Anticoagulation fact sheet-Warfarin".

There's also lots of other very useful info about Vit K rich foods, self testing(which isn;t suitable for everyone) etc etc.

http://www.anticoagulationeurope.org/

Also the yellow books also have information in them, so sometimes an idea to refresh ones memory by reading it if it's been a while.