My target Inr is 4
Was 4.7 but crashed down to 2.7 in 11 days why does this happen ??
Lucky my blood was 4.7 at the start if it had been on the lower edge of my range say 3.5 it would of gone down to 1.5 must certainly would of had suffered some kind of clotting avent !!! Had major stroke in 2011 and many Tia's
Hi Tim
This kind of thing can happen if you increased you consumption of Vit K rich foods; Vit K being a Warfarin antagonist. Brussels sprouts used to hit my INR badly.
Dave
Mine can go from 4 to around 3 in 24 hours, usual culprit is me forgetting to take my warfarin. 
I have a number of checks in place but can still get distracted. Thankfully I self test so pick up issues within a short space of time and act as necessary, either modifying dose or using Fragmin. On many occasions I would swear that I had taken my normal dose- but inevitably I had missed it.
Less frequently something I have eaten or drunk can make a difference- either way. A lot can happen over 11 days!
It need not follow that you will suffer some clotting event with a low INR, but for sure the risks will increase, and that is why we take warfarin, to reduce the risks. Do you know what your INR was when you had any of the TIAs? ( I have had them at 3.3) but I did have a hole in the heart which increased the likelyhood.
It sounds as though you might benefit from self-testing, though it doesn't suit everyone. What is your target range? Mine is 3.8 to 4.0 and , on advice of Prof Hughes, I self-test every other day and take Fragmin if I am below 3.0
Not sure if you are relatively new to warfarin, it can be quite a scary thing to be put on 'for life' - but if it helps, I have been on it for over 40 years so I reckon it truly is 'for life' - even if I do very occasionally miss a dose.
I should have added that some people do not get on with self-testing machines, especially if they are Lupus Anticoagulant positive like me (and Kerstin)
Hi there Tim,
As Tim 47 says (many Tims here) I can also change INR one number in 1-2 days. I actually have never forgotten to take my Warfarin yet. If I change I usually only change 1/4 of a tablet of 2,5 mg up or down. I also selftest every second day . Ask to selftest and get a Fragminshot under perhaps an INR of 3.0 (depends on what the doctor suggest). They are usually afraid you will bleed, but it is more likely we clot from this illness. My therapeutic range is 3.2 - 3.8 and I feel best at 3.8
Best wishes from Kerstin in Stockholm
Hi My INR should be between 4.5/5 as i have had so many clots unfortunatly the hospital struggle to keep mine in range its goes up and down all the time i am tested twice a week at GPs surgery i take anything from 40/50mg daily and it still will not stay in range they now say i have come resistant to warfarin i have been on it over 24 years now i ave tried a new thinning drug but i had bad side affects so was put back on warfarin i am hoping one day somthing else will work for me , i cant have sub cut heparin either as i am allergic to it.
I have just had to learn to put up with it and just have to be admitted to hospital for IV medication.
Is it possible to selftest?
Kerstin
Hello Kerstin
I bought my own machine from roche but i was told i could not continue to use it as i had 3 very wrong readings in 1 day i ended up in A&E being admitted as i had a blood clot in my lung while in hospital they used my machine and sent samples from my vains and yet again readings wrong so i was told i should not continue self testing , even now my INR is up and down all the time i do know when this happens as i get very tired and end up with migrains its only when its about 5 i feel well , And when it decideds to go very high i feel very ill.
If you have the possibility to selftest, do that. Much easier. I today took a Fragmin-shot as my INR had moved 0.9 from yesterday as I have an influenza-virus with fever just now. The INR was under 3.0. I also have taken Paracetamol which also may alter the number and have not exercised in 2 days. Those three tings alter the INR.
Kerstin in Stockholm
A blip with my inr!
Why is my INR so low?
Does anyone suffer from headaches and dizzyness when inr is too high?
INR Crazy times! 
