Atrial fibrillation

What is it like being on warfarin for atrial fibrillation?

Blood thinning medication (anticoagulants) such as warfarin can help reduce the risk of stroke for people with atrial fibrillation (AF). We asked people how they felt about taking warfarin. They told us their concerns about the increased risk of bleeding, attitudes to blood testing, self-monitoring, and the interaction of warfarin on diet and medication. 

Increased risk of bleeding
While the association of warfarin with rat poison was rarely a deterrent, fear of bleeding and the inconvenience of regular blood tests to check INR levels (INR, or international normalisation ratio, measures how well your warfarin is working) were concerns for many people with atrial fibrillation (AF). 

One of the side effects of warfarin is an increased risk of bleeding. People we spoke to reported an increased tendency to bruise, cuts taking longer to stop bleeding, and a fear of falling and cutting themselves. Jenny mentioned how her husband knocked a small wound on his hand while on warfarin and bled profusely, and Nuala described ‘a lot of bleeding’ when she had a tooth removed. Gail’s face was ‘really swollen and bruised’ after having dental work done while she was taking warfarin. Elisabeth Y’s decision not to take warfarin was influenced by the circumstances surrounding the death of Scotland’s first First Minister, Donald Dewar, who had a ‘massive cerebral bleed’ after falling and banging his head while on warfarin.
Some people we spoke to wore bracelets or tags or carried booklets to alert people to the fact that they were taking warfarin for their AF. Paul’s bracelet has his condition, blood group, name and date of birth on it. Raymond also wears an alert bracelet – ‘It tells everybody what’s happened to me, that I’m on pacemaker, that I’m on warfarin.’
Attitudes to blood testing
Being on warfarin involves regular blood testing to check INR levels.
Some people we spoke to viewed it as a small inconvenience worth putting up with. Geoff, who has his blood test on the way to work, described how ‘it only takes fifteen minutes and they give you a little pin prick and they give you the results straight away’. Glyn praised the ‘new machine’ at his GP surgery which tested his blood with a finger prick test and provided immediate results so that his doctor could adjust his levels of warfarin if necessary.
Audio onlyText only
Read below
However, bruising from regular blood tests and the inconvenience of attending anticoagulation clinics or GP surgeries for blood testing were issues for others. Regular blood tests left Paul’s arm looking ‘like a pin cushion’. For Ginny, who lives in a rural area, regular trips to hospital to have her blood checked proved expensive and time consuming, as well as interfering with her work. Others also found the regular blood testing quite difficult to fit in with work commitments. Dave, whose job involves frequent overseas travel, described the prospect of being on warfarin and having regular blood tests as ‘seriously inconvenient and an awful lot of irritation’ and decided not to take it. Dot found the process ‘a drag’ and ‘a big chunk of time and disruption every week’. Adjusting warfarin levels after blood testing could also be a problem.
Home monitoring of INR levels
Home monitoring of INR levels can be a solution for those who find attending clinics for regular blood tests inconvenient. For some, home monitoring offered them increased independence and a sense of control in regulating INR levels. However, self-monitoring was not always appropriate or freely available. Dot was told that she could self-monitor once her INR was stable so long as she bought the machine and testing strips herself. Nuala would find it useful to self-monitor as ‘it would give me more independence’, but her medical team are less enthusiastic.
Interaction of warfarin on diet and medication
Some people taking warfarin talked about its interaction with certain foods and drink. They found foods such as cranberry juice and grapefruit, or going out for a big meal or a few more drinks than usual could affect warfarin. However, not everyone found it easy to identify the dietary cause of INR fluctuations. As Raymond said, ‘I don’t know what bit of the diet causes this to go wrong’. Nuala followed the advice of her doctor to ‘eat whatever you want and I’ll warfarinise you’. This has given her more freedom in dietary choices.
People we spoke to told us that prescription medicines and over-the-counter products such as antibiotics, ibuprofen, aspirin, cough medicine and vitamins could also interfere with their INR levels.
(For more see ‘Atrial fibrillation, stroke risk and blood thinning medication’ and ‘Alternative to warfarin for atrial fibrillation: the new anticoagulants’).


Please use the form below to tell us what you think of the site. We’d love to hear about how we’ve helped you, how we could improve or if you have found something that’s broken on the site. We are a small team but will try to reply as quickly as possible.

Please note that we are unable to accept article submissions or offer medical advice. If you are affected by any of the issues covered on this website and need to talk to someone in confidence, please contact The Samaritans or your Doctor.

Make a Donation to

Find out more about how you can help us.

Send to a friend

Simply fill out this form and we'll send them an email