How do doctors start people on Warfarin?

I have been put on aspirin, as I explained in a previous post, and I would like to go back to the doctor and ask to be put on Warfarin. However, I have the impression that it's a bit of a faff, particularly to start with - a lot of testing and such like. Am I right? Can anyone talk me through what the doctor will do in the first month or so? If I can persuade him that is...

19 Replies

  • Hi Lottie, In my experience it was actually quite easy but different doctors do different things. Some star you on a very low dose and build up gradually over a few days testing say every other day. Mine gave me a large dose and checked after two days and then started adjusting till I was in range. Ideally for AF if you are at risk your INR should be between 2 and 3 say 2.5 . The most important thing to remember is not what you eat so much as being consistent about what you eat rather than swapping your diet and having binges on one type of food then not for a few days. You will be given a book on things to avoid like Cranberry , Grapefruit and Broccoli which can affect your INR and told to keep you alcohol intake lowish and consistent. Ive been in the stuff for years and am reasonably stable so little problems. Good luck convincing your GP.


  • Thanks BobD! I guess it makes sense that every surgery will have their own approach. I think I will need the luck - I'll let you know what happens :)

  • Hi Eatsalottie,

    I started on warfarin in March and have a feeling that starting on it may vary from surgery to surgery or anti coag. clinic, but here's my experience. I first of all had a blood test to find out what my actual INR was prior to starting, and mine was 1.1. I suppose this gave my GP a baseline. It's not exact science as everyone varies in the amount they need to take in order to reach the required INR, in my case we were aiming for 2 to 2.5. It is so much trial and error, and I started on 3 mgs.

    My surgery has a finger prick coaguchek machine so it's so easy, I just see the nurse have my finger stabbed and we wait a few seconds for the result. Later the nurse passes the result to my GP and one of the receptionists phones me, usually some time in the afternoon telling me how much warfarin to take and when to be next tested. Every so many patients get tested from a venous sample sent to the lab to make sure their machine is calibrated OK. I haven't drawn the short straw yet.

    3 mgs wasn't enough so it was upped to 5mgs, which proved to be too much, 4mgs proved to be the right dose for me. To start with I was tested twice a week, but I very soon was down to once a week, and then once a fortnight and now once a month. I wanted to visit a friend in Suffolk during the early stages and we organised a test at her surgery as a temporary patient, and some people buy their own machines and do their own testing so it doesn't have to be restrictive.

    An INR fluctuates with diet, and food rich in Vitamin K like green leafy veg, will lower it, I haven't changed my diet but I have been lucky as I seemed to stabilise very well. There's lots of good info available about it.

    Hope this is fairly clear and helps. It is very much trial and error in the beginning because we are all so different.

    It was a bit of a fiddle to start with but not for long. Now it's just part of everyday life, and what a small price to pay for stroke prevention. I'm off it for a while and I feel I've lost my security blanket.

    Good luck especially with your GP. You need to wave the appropriate AFA info under his nose. Stay well, Liz

  • Thank you! That is very helpful indeed... It sounds manageable so all I need to do now is pluck up the courage to go visit him again. I will print off the AFA info for nose-waving purposes! You stay well too Lizzily, take care.

  • Hi Eatsalottie

    Have just been sorting out my mountain of AF stuff in order to write up my list of questions for the cardio this week, and came across the print out of my stroke risk calculator, which I did from the AFA web site, and had a thought. Would it be useful for you to check your risk using this tool and to take the result to your reluctant GP. It shows the old way of scoring with the CHADS2 method and the newer safer score of CHA2DS2VASc. I only score 2 for being female and over 65 but it's enough to put me at high risk and it clearly states "treat with anticoagulation therapy". Happy Sunday, we still have cloud but it looks a bit brighter on the horizon. Liz

  • Hi Liz

    Our GP had the CHaDs2Vasc (however it's spelled!) score, and I score 1 for being female, which means he should only 'consider' anticoagulation. It seems his, and the generic NHS view is aspirin first then warfarin if it gets worse. I'm sure from what's going on in the US, Japan and elsewhere that eventually the NHS will overturn this, but we're talking about a little, rural surgery that's probably not very up-to-speed with current thinking (not like the fantastic, helpful people on this website). So I have some persuading to do! Happy Sunday to you too - we have cloud and sunshine here, but I too am hoping for a brighter horizon. Lis

  • Hi again,

    I have just looked at my printout and if you score 1 on the CHA2DSVASc score it says "moderate risk, recommend anticoagulation therapy over aspirin" can't see the word "consider" anywhere!! Recommend feels a much stronger word than consider. I wanted to be considered for ablation without taking any anti arrhythmic drugs, which is against the NICE guidelines, and took the printout from the European Soc. Of Cardio's to my GP, which agrees with this. He now looks as if he wants to hide under the desk when he see's me, well, not really, but have one precious life which is worth fighting for. Sunshine now, off for a walk soon to blow the cobwebs away. Liz

  • Hi Eatsalottie

    It's not so bad, and you very quickly get used to it, you will either be treated at your surgery or a local anti-coagulation clinic, they will usually first take you in, have a chat to you about warfarin, and measure your INR and it will be 1, and what they aim for, as Bob D says, is to get you between 2 and 3 INR, that's your blood will take two to three times more to coagulate than without warfarin.

    They'll give you 3 packets of pills usually, all different strengths and recommend a starting dose, and the one week later usually, very quick blood test to measure your INR and then they adjust the dosage up or down according to how you have tested. Some of us (me for example) take ages to settle down, so I was on weekly testing for 13 weeks, but that's rarer most people move out to two weeks in about 3 or 4 weeks, and then usually out to monthly testing as soon as you have a settled INR.

    You'll also get a yellow booklet to record your INR results, and you need this to renew a prescription, or also to see a dentist as they need to know your INR before they treat you.

    As Bob says, it's not about what you eat, but about the consistency of what you eat, don;t binge and stay clear of cranberries.

    I've heard very little from people about side effects, they do exist but seem fairly rare, just remember you will bruise more easily, especially at first, and you may have to give up being a professional stunt man or rugby player for the risk of bleeds :)

    Honestly I don't even think about it now, once a month up to the clinic for the blood test, chat to people who I have got to know, go home, and merely pop down the pharmacy if I am getting low for them to fill my repeat presription. Easy Peasy Lemon Squeezy as my granddaughter would say.

    Be well Ian

  • Thank you Ian - of course I'm bitterly disappointed that a career as a stunt granny is now closed to me but I'll try to be brave :)

    It's very good to have an idea of what is likely to happen if and when I persuade him to put me on warfarin, it sounds less hassle than I had thought it might be. Easy Peasy Lemon Squeezy is definitely good!


  • Hi Lis

    I agree with those who have already written. Taking Warfarin really is not much of a problem. I am still having to have weekly checks as my INR fluctuates quite a bit, but my surgery is only a few minutes away and the finger prick test only takes a second and the nurse`s computer programme quickly tells her the result and relating recommended dosage almost immediately. Some people do buy their own machines, but I believe they cost several hundreds of pounds. However, depending on your personal circumstances it may well be worth the investment.

    There are of course other anticoagulants available, but not all doctors seem to prescribe them ( not sure if they are generally available in all areas). From a personal standpoint I prefer Warfarin as it has been well tried and proven effective over many years.

    Wishing you well


  • Hi Anthea, and thank you - it's great to have all this information. Warfarin is the only option our surgery offers, apparently the health board won't pay for anything else so I guess that's it. The more modern anti-coagulants would be better in terms of not needing all these checks, but I am not being given that choice. However, warfarin doesn't sound as fiddly as I'd feared, so I'll make that appointment and ask the question!

  • Eatsalottie I was concerned about the faffing about with warfarin but have been very lucky. Our surgery uses coaguchek machine so finger prick then nurse punches result in and computer spits out a print of daily dose and date for next check. She can override if date is not convenient. I do know hard it is to try and suggest change of treatment to GP. Good luck. Wendy

  • Thanks Wendy - I think the surgery does have a coagucheck machine (doctor mentioned a pin prick so I assume they're doing something with it afterwards!). I am steeling myself to talk to him about it and all your good wishes are very much appreciated.


  • Hi wendy when I first took AF I was put on asprin, but the side effect where to bad for me so my doctor put me on wharfrin and I.m now okay (steady 2.4 to 2.8 .) yes there is a bit of ups and downs and blood testing checks to find a stable nir but after that it.s easy peeeeesy speak to your gp about whafrin

    good luck

  • Thanks watchdog - I didn't realise there might be side effects to the aspirin! I guess there are side effects to everything... I will speak to my GP, thanks for the feedback.

  • Have you thought about Pradaxa instead of Warfrin? I had trouble getting my levels anywhere near right with Warfrin, so went onto Pradaxa with instant success, no side effects and very simple to use. Only downside was cost, this has changed in Australia now and is subsidised. Worth looking into.

  • That's a bit of a sore point John... The doctor said our health board would only allow them to prescribe Warfarin, so it's Warfarin or nothing. I've been reading bad things in the papers about the board, which is 'in disarray' and up before the Welsh government for various failings. It sounds from the stories as if their main concern is cost, rather than patient care, so I think I'm a bit stuck there :(

  • I've been on Warfarin for six years now, it took months to get me at a suitable level, and I don't think I have ever had a consistent reading ever! I take 11 mgs daily. It seems a lot considering that my diet hardly changes. It can sometimes go down to 1.8 then in a matter of weeks go up to 4.00. I do go to my gp now rather than the hospital which took hours every week, at least it's about half an hour in all with dr.

  • Thanks, MissL... Your experience goes to show, I think, how very differently people react to different drugs - I'm on Bisoprolol and seem to be fine with it (touch wood) yet I've seen other people write and say they've had bad reactions. I suppose it's always a case of trying something and seeing if it works... Sorry you've had a bad experience with it and I hope it settles down.


You may also like...