cranberries, colorful berries, food-drug interactions

Q. Does aspartame affect bleeding if you are taking a blood thinner like Coumadin? I know that cranberry juice poses a potential problem with this drug. How can I keep up with Coumadin interactions?

A. Coumadin (warfarin) is a life-saving drug but it can be tricky to use. This medicine reduces the risk of blood clots that can lead to strokes or heart attacks. Getting the dose right, however, poses a significant challenge. Too much or too little drug can be dangerous.

Many foods and other medications can interact with Coumadin. When a person taking Coumadin drinks a lot of cranberry juice, the risk of dangerous bleeding may rise. Several cases have been reported, but scientists are still debating the clinical significance of the interaction.

Aspartame (Equal, Nutrasweet) is an artificial sweetener that may increase bleeding time (Clinical Pharmacology and Therapeutics, Feb. and May, 1998). Although this interaction is controversial, we would encourage anyone consuming aspartame and taking Coumadin to monitor the impact on bleeding very carefully.

Sorting out all the dangerous food and drug combinations with warfarin is complicated. Our free Guide to Coumadin Interactions is available at

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  1. Ann
    Albury NSW

    Following a stroke in 2002, Atrial Fibrillation set in and I was put on Warfarin. I have not had a stroke since. I still have AF but I cope better these days. I am 75 yrs. old.
    I do not drink alcohol or smoke and avoid foods with Vit K. I find that dieticians know very little about what does not mix well with Warfarin. I have read that Parsely has an enzyme which could be fatal, also camomile, green tea and other things which we know little about.
    I am being advised to start iron infusions but I am not sure of the side effects.
    I think that a chance to discuss the matter with others is a good idea. Many thanks – Annie B

  2. FRANK

    Hi Stephany. My name is Frank. I mailed you a few years ago and I just found your address again via the “people’s pharmacy”.
    I encl. their address for your info. guess they are trying to sell this this doctor’s book …how to deal with certain drugs (coumadin ect) and doctor’s prescribed med’s that could be fatal for some people. anyway, just wondering how are you doing with keeping inr.’ ?? in check. thank god, so far have been well within the range -2.0 to 3.5-. going for my blood-test once a month now. I am a lifer as well – now taking 6.0 mg daily and watch what I am eating / consuming.
    would be nice hearing from you.

  3. Klh

    I’m a homozygous Factor V Leiden copy individual. We found out when I was 67 or so and got diagnosed with “post” DVT … short story is now I’m on it for life. Interesting to read all these comments especially the ones from users who worry that their INR is “unstable” when it fluctuates between 2.2 and 2.6. Anything between 2 and 3 is acceptable. I wish I didn’t have to be on this anticoagulant (not “blood thinner” as commonly called) and will probably one day tell the medical community to get stuffed and take myself off of it. Meanwhile, I lay off Vitamin K veggies, alcohol, artificial sweeteners and n-saids and try not to complain.

  4. crystal

    I have been on coumadin since September of last year I was only suppose to be on it for six months but here I’m still on it a month ago my inr was 3.5 and my doctor lowered my meds to 7.5 from 10 ever since then its been going from 1.9 now till this day1.6.
    I also have pain in my other leg, could I have a a blood clot in my other leg??? My legs also sometimes keep me up at night. Thank you for the comments some helped me out

  5. Tonja

    Yes my counmadin level was low for a good long time 1.1 my doctor changed my dose to 3 tabs of 5mg a day. It was too much so he changed it where I would take 15mg on Monday then the next two days tues and wed I would take only 10.
    It’s really strange because it seems to work but before these clots formed in my left leg from top to bottom I didn’t take pain medicine even, I ate pretty clean but I stop being as active for 11months was dehydrated and took a long drive and came back with clots, now I’m also on iron and vitamin c twice a day but if your level stays low talk to your doctor about upping your dose or foods you may be eating. Just ask questions and express your concerns. I’m still having tests done to make certain.
    I don’t have a clotting disorder , I have one last test to take… ok guys be healthy and safe’

  6. P.K.

    I am on Coumadin for several years–Now it is low and I can’t seem to get it up. It was 2.3 – 2.6 but now it is 2.1–I love salads but have limited them to about 1-2 a month and just after I have my INR—I am also a Diabetic ! so I have to check that also. Boy oh boy what do I do??? P.K.
    People’s Pharmacy response: The best practice is to get the same amount of greens every day.

  7. amy

    Not seen a lot on here about LOW coumadin and ppl really having a lot of trouble, and I am meaning LOW. For 3 months now every 4 days I have been getting my pt/Inr checked. It has been @ a 1 @ a 1.1 and it’ s now ONLY A .98, not even a 1. I have small veins and don’t have enough oxygen in my body, and have copd I am on 3 liters of oxygen, a lot of time IF it is cool, not too hot I will try to take it off a lil while. But I also have trouble keeping my potassium level up.
    So now I am fighting to keep myself alive I guess. But what I am wanting to know from anyone is has anyone else had theirs this low and getting checked every 4 days and still not coming up. What can I do??? I am really getting scared right now w/ it being this low for 3 months? Can someone tell me what else I can do?

  8. frank

    Hi Stephany. My name is Frank.
    Came across your info on factor V leiden and problems with blood clots. 7 years ago I went through the same situation. Both lungs were shut with clots except for the left one which was only 1/3 open. Barely hung on to live!!! Had a lot of associated health problems since. Taking 7.5 mg daily but still the INR is unstable – between 2.2/ and 2.6 and watch my diet very carefully.
    Just wondering how you are coping?
    Guess being a “factor V leiden” candidate we should be thankful for having … Coumadin… Take care, and well. Frank

  9. Marilyn

    I have been on coumadin for 20 years. Initially I had some difficulty regulating it but for the last 9 years it has ranged between 2.0 and 2.5. My cardiologist doesn’t want me to go below 2 or above 3. I drink a little wine on occasion, take Vitamin D, C, Salmon oil and glucosamine. (the latter 2 are new and I haven’t checked my INR since taking it – will do so next week. I also eat a lot of vegetables (K veggies too) with little problem. If I see that my INR is too high or too low I adjust my dosage of coumadin and get checked within the week. Otherwise I get my INR checked every 4-6 weeks. My family on my mother’s side died from strokes and clots so I feel much better about taking coumadin.

  10. AG

    I have been on Coumadin for a few months now. I was told I needed to be on it for 6 months after discovering I had bilateral pulmonary embolis (2 blood clots in each lung) due to a surgery. They told me to take it for 6 months and I should be fine and to just stop taking it afterwards. I asked the doctor if they were gonna do another scan to see if everything was good and he told me there was no need. I was getting my INR checked twice a week at first, then once a week, then every 2 weeks and now it’s once a month. Does this sound normal? Is this how it normally is?

  11. Karen L.

    I’ve been on coumadin since shortly after my second open heart surgery, when I was 44. I was born with heart defects in 1947. They were not diagnosed. Somehow, I grew up. When I was 34 I had a large hole patched. Then at 44 I had my mitral valve repaired. A few years after the second surgery I developed atrial fibrillation. I was put on coumadin, was told it was for life. In 2006 I had radiofrequency ablation, which often “cures” arrythmias and eliminates the need for coumadin.
    However, they could not fix the arrythmia that was behind the patch on my large hole. Plus they nicked me during the procedure and I bled internally. I was told I’d still have to be on coumadin for life. It is a horrible drug, my levels are either too high or too low. I have bipolar disorder too, and get mixed up all the time. I am 62 now. I am divorced and completely alone. I worry constantly about what if I get hurt. Sometimes my nose oozes blood.
    I’ve had my nose cauterized but it could still bleed. I eat a varied diet, I am very poor, so whatever I can afford, I am on Social Security Disability. I would appreciate input, and also for anyone: be very careful on this drug, it has such a high rate of interactions with everything, from food to other drugs to over the counter drugs. I am well educated and I still get weird INR levels. Thanks for reading this, I am at my wits end. “Don’t get injured” so “they” tell you, well what if you fall or get into an accident?

  12. D.A.L.

    I have been on Coumadin/warfarin for about six years now due to pulmonary embolae in both lungs (3). The clots traveled from my legs to my lungs. I’ve been taking it for about (6) years now. My protime levels are usually good. I sometimes feel a lot of anxiety and find it hard to sleep. Is this normal? I also have allergies and sometimes the effects feel exaggerated, I suspect that maybe since my blood is thinner the symptoms are magnified.
    Any input?

  13. carol

    I have been on cumodine for three weeks due to complete knee surgery. I have Osteoarthritis pretty bad. I stopped my Calcium Mag vitamins. Can I resume them now?

  14. J. Snow

    My dad had congestive heart failure 2 years ago and was put on coumadin. he bruised all the time and had blood in his urine. They NEVER got his level right. So he quit it all and began using vitamin E, and gingko biloba. It worked PERFECTLY. Our family owns a health food store, so we know a lot about this. Unfortunately, he died on July 30, 2009 of a massive heart attack, even though his cardiologist said two weeks earlier he was fine. We believe that the coumadin weakened his veins and contributed to his death. He bears some responsibility, because his diet wasn’t always the best. But I, his son, believe he would be alive today if he had not taken coumadin. It ain’t no miracle drug.

  15. LLJ

    I’ve had the same experience, my Dr. put me on 2 salmon oil caplets a day. At first I just took one and my INR was very low, so I had to increase my coumadin dosage. Then I began taking two salmon oil caplets and once again, my INR is low. I keep telling them that I think it’s the Salmon Oil, but I don’t think they believe me.

  16. Jo

    My husband JUST started taking coumadim. He has bilateral pulmonary embolis and is currently in the hospital. I want to thank all of you for such wonderful and educational information which is helping me to understand the pros and cons of coumadin. Stay healthy everyone, and thanks.

  17. C.C

    I have been on Coumadin since 2000. I am severely anemic, I have to have iron infusions weekly. My hemoglobin count is presently at 6.8. I am weak and tired all the time. My appetite is poor. I am having the hardest time eating. I love the greens but I know that this will put my INR/PT out of range which is 2.5-3.5. I have a history of intestinal bleeding how or why I don’t know. If I am to beat this I need to understand how the drug works. Any help will be greatly appreciated.

  18. JSK

    I’ve been on Coumadin since my valve replacement surgery almost four years ago. If you can’t get your INR level to stabilize, I have a suggestion. Find the list of things that negatively affect your level (foods, etc) and stop consuming them. I don’t drink alcohol (not even a beer) and I don’t eat the high vitamin K veggies. My levels stabilized about 4 months after surgery and haven’t changed since. If you are trying to have it both ways, that won’t work. You have to sacrifice some of the foods you might love for your health. Try it.

  19. stephanie

    January of this year, I discovered i had a DVT (11 in. long) in my left leg. By the time it was found, part of it had broken off and traveled to both lungs. I was diagnosed with Factor V Leiden and Lupus Anticoagulant Inhibitor and will most likely remain on Coumadin for the rest of my life (I was 39 when this happened). I have been on Coumadin for 5 months now and it still has to be adjusted every two weeks. They want me between 2 and 3, and it NEVER is. My advice to anyone taking it (which is what I have started doing myself) is write down EVERYTHING you put into your body. Every leafy green veggie, every otc pill, every sip of alcohol… then hopefully we will be able to decipher what causes the huge level changes and finally get it regulated.

  20. rrflac

    I am looking for an online resource for researching interactions between western pharmaceuticals and western/chinese herbs and neutraceuticals! (ie coumadin and DGL or Pill Curing formula?)

  21. Ann Hayes

    I’ve been taking Coumadin for about ten years. Nine months ago, the doctor put me on Salmon Oil gelcap (to raise my good cholesterol) and everything I’ve read since on the subject said it would thin my blood even more, but that’s definitely not been my experience. I have had to increase my dose slightly to keep my INR in the 2 – 3 window. I’m taking 3 gelcaps a day

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