Warfarin and bleeding, side effects, safety, danger and risk, use and interactions with natural supplements, herbs and vitamins, nutritional pills by Ray Sahelian, M.D.
November 20 2017

Warfarin sodium is derived from coumarin -- a naturally occurring chemical compound with anti-clotting properties found in many plants. It thins the blood and was originally used as rat poison. Treatment reduces the risk of thrombosis (blood clots), but makes patients more liable to bleeding and use is associated with an increased risk for brain hemorrhage. Warfarin is effective at reducing the risk of stroke in atrial fibrillation.
   Warfarin is one of the most widely used drugs taken by 2 million patients to prevent blood clots that can cause heart attacks and strokes. It is also sold under the brand name Coumadin by Bristol-Myers Squibb .

Natural supplements and warfarin interactions, caution with other natural blood thinners
Certain supplements have blood thinning potential and should be used with caution by those who are on blood thinning medication. See blood clot for more information. Consult with your doctor. It is possible that the use of certain supplements, or dietary changes that include more fish, spices and vegetables, could reduce the dosage required for warfarin. Natural supplements that thin the blood include:

Bee Pollen
Am J Health Syst Pharm. 2010. Probable interaction between warfarin and bee pollen. A 71-year-old Caucasian man arrived at an anticoagulation clinic for routine warfarin monitoring with an International Normalized Ratio (INR) value of 7.1 (therapeutic range, 2.0-3.0). His medical history included atrial flutter, hypertension, hyperlipidemia, diabetes mellitus, erectile dysfunction, obesity, and hypothyroidism. His medication regimen included warfarin, hydrochlorothiazide, lisinopril, levothyroxine, simvastatin, glyburide, metformin, vardenafil, aspirin, a multivitamin, and the herbal products Cataplex E2, Cataplex B, and Cyruta. The dosages of all medications and herbal products had been stable for the previous nine months, including warfarin (INR, 1.9-3.3). The patient began taking bee pollen granules (one teaspoon orally twice daily) for a perceived general health benefit one month before this clinic visit. He denied use of alcohol and tobacco, changes in dietary phytonadione intake, missed or extra doses of warfarin, any other medication changes, and acute illness and diarrhea. Warfarin was withheld, and the patient was seen at the anticoagulation clinic three days later with an INR of 3.7. Warfarin was held for a fourth day and then restarted with the weekly dose decreased by 11%. The patient continued to take bee pollen, and all INR values during the next seven months were within or near the therapeutic range. Use of the Drug Interaction Probability Scale indicated that there was a probable interaction between bee pollen and warfarin. Consumption of bee pollen led to increased INR values in a patient taking warfarin.

Chamomile is a mild relaxer and has very mild blood thinning activity. Canadian doctors describe the case of a 70-year-old woman, while being treated with warfarin, who developed severe internal bleeding after drinking chamomile tea to soothe a sore throat and applying chamomile lotion to relieve chest congestion and reduce foot swelling. While warfarin is known to interact with garlic, onion, and ginger, this is believed to be the first documented case of a drug-herb interaction between warfarin and chamomile. In the present case, the woman had received a mechanical heart valve implant and was taking warfarin to reduce the risk of blood clots. Canadian Medical Association Journal, 2006.

CoQ10 supplement - Is Coenzyme Q10 safe to take in those who are on warfarin therapy? The results from studies have been inconsistent, and my impression is that low dosages of 30 mg a few times a week should not interfere with warfarin medication.
Cranberry juice, sauce or cranberry supplements thin the blood and increase INR levels in patients who are taking warfarin pills.
Dong quai herb is a Chinese herbal supplement which has natural coumarin derivatives. Dong quai increases the effect of warfarin, increasing the risk of bleeding; therefore, co-administration is contraindicated.
EGCG, the extract from green tea, may prevent platelet aggregation as potently as aspirin.
Fish oils thin the blood and their risk in combination with warfarin depends on the dose of the fish oils and the dose of the blood thinner. Those who take fish oil pills may need to reduce their dose of prescription anti-coagulants since it is possible that the INR can increase with supplementation.
Cayenne supplement may increase the risk of bleeding with the use of warfarin medication.
Garlic is a mild blood thinner.
Ginger may increase bleeding risk in those who are taking warfarin pills.

Ginkgo biloba is a Chinese herb used for mental enhancement and alertness and is one of the most widely used herbal products in the United States. However, bleeding episodes in patients taking ginkgo biloba and warfarin have been documented. Ginkgo extract inhibits human liver microsomal CYP2C9.

Nattokinase is a potent blood thinner compared to other natural herbs and supplements. Always consult with your doctor before taking nattokinase, particularly if you are taking warfarin.
    Q. My Dr. put me on warfarin. I was taking it for about 3 weeks when I had such a severe reaction to it that I told him that I would no longer take it. Of course he issued me with many dire warnings and said that it was very safe and had been used by the medical profession for a very long time. I told him that may be the case but it was not my experience. A friend told me about nattokinase and I ordered a bottle of 9 months supply. Nattokinase has been banned for sale by Health Canada, hence my order goes to our US mail address where I am able to pick it up. I have taken it for two days now and feel relieved that I am taking it as opposed to warfarin. What are the effects of taking fish oil and turmeric with nattokinase? I had a stroke in 2009 and was diagnosed with Type 2 diabetes in the same year.
   Answer: Fish oils act as blood thinners and so does nattokinase. I have not seen studies combining the two supplements. Turmeric is not a potent blood thinner.

Onion is a potent natural blood thinner.

St. John's wort may increase the risk for bleeding when used together with warfarin medication.
Vitamin K helps blood coagulate.
White willow bark supplement
     This is a partial list.

Nat Prod Commun. 2014. Warfarin interactions with medicinal herbs. Potential herb-drug interactions are of a major safety concern, especially for drugs with narrow therapeutic indices like warfarin, which can lead to severe adverse reactions that are sometimes life-threatening. The interactions between warfarin and medicinal herbs described in the literature have been summarized in this paper relying on Medline database (via PubMed) using the key words: warfarin, herbal supplements and interactions. The references on the analyzed literature have been investigated in order to collect the existing data. The case reports with severe adverse effects such as spontaneous postoperative bleeding, formation of hematomas, hematemesis, melena, thrombosis, subarachnoid hemorrhage and/or subdural hematomas after concomitant use of warfarin and the medicinal herbs: Panax ginseng, Hypericum perforatum, Salvia milthiorizza, Gingko biloba, Serenoa repens, Angelica sinensis, Vaccinium species, Allium sativum, Zingiber officinale, Tanacetum parthenium, Lucium barbarum, Matricaria chamomilla, Boswellia serrata and Camellia sinensis have been estimated. Some of the interactions between warfarin and medicinal herbs have been well assessed proving that they are closely-dependent. The interactions between warfarin and medicinal herbs, not generally reported in previous reviews, are presented in our review.

Q. I take warfarin and cannot find any joint products that do not contain the herbs I cannot take. Do you have a product that would be okay to take with warfarin.
   A. There are many herbs that have blood thinning potential. Since few herbs have been studied in relation to blood thinning or interactions with such medications, it is difficult to give any definitive recommendations regarding which herbs or supplements are safe with this blood thinner.

CoQ10 and warfarin
Effect of Coenzyme Q10 and Ginkgo biloba on warfarin dosage in patients on long-term warfarin treatment. A randomized, double-blind, placebo-controlled cross-over trial.
Ugeskr Laeger. 2003. Engelsen J, Nielsen JD, Hansen KF. Klinisk Biokemisk Afdeling, Koagulationslaboratoriet, Amtssygehuset i Gentofte, Hellerup.
A few case-stories claim that the anti-oxidant Coenzyme Q10 and possibly also Ginkgo biloba interact with warfarin treatment. A decreased response to warfarin in the Coenzyme Q10 cases and an increased response in the Ginkgo biloba case have been described. Twenty-four outpatients on stable, long-term warfarin treatment were included in a randomised, double blind, placebo-controlled crossover trial. Coenzyme Q10 100 mg daily, Ginkgo-Biloba 100 mg daily and placebo were given in random order over treatment periods of four weeks, each followed by a two week wash out period. The international normalized ratio (INR) INR was kept between 2.0 and 4.0 by appropriate adjustment of the warfarin dosage. Fourteen women and ten men, median ages 64.5 years (33-79) were included. Three patients withdrew from the study for personal reasons. The INR was stable during all treatment periods. The study indicated that Coenzyme Q10 and Ginkgo biloba do not influence the clinical effect of warfarin.

Nat Prod Commun. 2014. Warfarin interactions with medicinal herbs. Recognition of the adverse effects of medicinal herbs is not routine and the reports on such effects are even less frequent in clinical practice. Potential herb-drug interactions are of a major safety concern, especially for drugs with narrow therapeutic indices like warfarin, which can lead to severe adverse reactions that are sometimes life-threatening. The interactions between warfarin and medicinal herbs described in the literature have been summarized in this paper relying on Medline database (via PubMed) using the key words: warfarin, herbal supplements and interactions. The references on the analyzed literature have been investigated in order to collect the existing data. The case reports with severe adverse effects such as spontaneous postoperative bleeding, formation of hematomas, hematemesis, melena, thrombosis, subarachnoid hemorrhage and/or subdural hematomas after concomitant use of warfarin and the medicinal herbs: Panax ginseng, Hypericum perforatum, Salvia milthiorizza, Gingko biloba, Serenoa repens, Angelica sinensis, Vaccinium species, Allium sativum, Zingiber officinale, Tanacetum parthenium, Lucium barbarum, Matricaria chamomilla, Boswellia serrata and Camellia sinensis have been estimated.

Warfarin side effects, safety, danger, caution, concerns
Hemorrhage (bleeding) is one of the most common and serious risk associated with warfarin therapy. The bleeding can occur in practically any tissue or organ. The signs, symptoms and severity of the bleeding and subsequent complications vary according to the location and degree of bleeding. Haemorrhagic complications may present as headache, hypotension, chest, abdomen and muscle pain, red blood in stools or black stool. Other side effects of warfarin therapy are necrosis of the skin or skin rashes, priapism, headache, and dark urine. Risk factors significantly associated with increased bleeding included high target INR (2.5 to 3.5), diarrhea, acetaminophen use, alcohol consumption, and increased age.

Warfarin side effects - Osteoporosis
The long-term use of warfarin appears to increase the risk of fractures associated with osteoporosis, a bone-thinning condition that usually increased with age. Warfarin prevents coagulation by blocking vitamin K, which is needed to activate certain clotting factors. Because vitamin K is also used to activate proteins involved in bone formation, drugs like warfarin may increase the risk of fractures. To investigate, Dr. Brian F. Gage, from Washington University School of Medicine in St. Louis, and colleagues assessed the rate of osteoporotic fractures among 12,048 Medicare beneficiaries. The subjects included 4,461 who had been prescribed warfarin for at least one year and 7,587 who were not on the drug. Warfarin users were 25 percent more likely to experience a fracture than nonusers. However, this relationship was statistically significant only in men. Further analysis of data from 1,833 patients who were on warfarin for less than one year did not detect a statistically significant increase in fracture risk. Risk factors for fracture included older age, high risk of falling, overactive thyroid, neurological or psychiatric disorders, and alcoholism, the report notes. When prescribing warfarin to elderly patients at high risk of falling, healthcare providers can instruct them to wear stable shoes, exercise regularly, have adequate intake of calcium and vitamin D, use walking aids, and discontinue unnecessary medications. Archives of Internal Medicine, 2006.

Trauma and injury
Warfarin may also cause problems for individuals who suffer some form of trauma, particularly the elderly. Trauma patients who take warfarin at the time of their injury are at increased risk of dying compared with trauma patients not on the anti-clotting drug.

Warfarin diet, food, what we eat
The effect of warfarin decreases after initiation of a high-protein, low-carbohydrate diet.

Warfarin alcohol
It's quite likely that alcohol interferes with warfarin metabolism and effect. Hence, it is preferable to avoid drinking more than one glass of alcohol a day. Wine has compounds called flavonoids that thin the blood.

Warfarin and stroke
In those with atrial fibrillation, is it superior to the combined treatment of the blood-thinner Plavix plus aspirin in reducing strokes? Many older Americans take the blood thinner warfarin to help guard against heart trouble. However, use of the drug is tied to a temporary spike in the risk of stroke for people with this common heart rhythm disorder. People with the irregular heart beat known as atrial fibrillation had nearly double the odds of suffering a stroke in the month after they started taking warfarin, compared to similar patients who weren't taking the medication, Vivek Reddy, M.D., director of arrhythmia services, The Mount Sinai Hospital, New York City; Neil Sanghvi, M.D., clinical electrophysiologist, Lenox Hill Hospital, New York City; European Heart Journal, news release, Dec. 18, 2013.

The rate of brain hemorrhages associated with blood thinning drugs quintupled during the 1990s. In people over age 80, the rate increased more than tenfold. Most of the increase is due to greater use of the drug warfarin, which is commonly prescribed to prevent blood clotting. Blood clots can lead to ischemic stroke, the most common type of stroke. An intracerebral brain hemorrhage is a stroke caused by bleeding in the brain. The use of warfarin increased after studies showed it reduced the risk of stroke caused by blood clots for people with atrial fibrillation, a condition that causes irregular heart rhythm and becomes more common as people age.

Warfarin drug interaction
Non-selective non-steroidal anti-inflammatory drugs (nNSAIDs) used in combination with warfarin are associated with an approximately 3-fold increased risk of upper gastrointestinal bleeding compared with warfarin alone.
    For women taking warfarin to prevent blood clots, a single dose of fluconazole to treat a vaginal yeast infection can lead to an increased risk of bleeding. The time taken for blood to clot -- the so-called prothrombin time -- should therefore be carefully monitored in this scenario, and a change in warfarin dose may be needed. Fluconazole (brand name, Diflucan) is a common treatment for vaginal candida infections, and is known to interact with a number of drugs, including warfarin -- which can give rise to serious bleeding complications.

In older patients on warfarin therapy, treatment with cotrimoxazole significantly raises the risk of upper gastrointestinal tract hemorrhage. The increased hemorrhage risk is considerably higher than with other commonly used antibiotics. Compared with amoxicillin or ampicillin, for example, cotrimoxazole increased the risk of upper GI tract hemorrhage by almost three-fold. Arch Intern Medicine 2010.

Warfarin therapy and alternatives
Elderly patients as a group may present more of a challenge in managing warfarin therapy because of alterations in pharmacokinetics from other medications, diet, and disease; pharmacodynamic changes; increased risk for hemorrhage; and difficulty in monitoring. The elderly, however, may derive the most benefit from warfarin therapy for certain indications, such as the prevention of stroke in atrial fibrillation or recurrent events following deep venous thrombosis.

Heart failure (HF) and atrial fibrillation (AF) frequently coexist and share a reciprocal relationship. The presence of AF increases the propensity to HF and can worsen its severity as well as escalating the risk of stroke. Despite the efficacy of vitamin K antagonists and warfarin for stroke prevention in AF, their use has numerous problems. These include their slow onset and offset of action, unpredictability of response, the need for frequent coagulant monitoring and serious concerns around the increased risks of intracranial and major bleeding. Three recently approved novel anticoagulants (dabigatran, rivaroxaban and apixaban) are becoming more popular in atrial fibrillation.

Thrombosis. 2013. Dabigatran, Rivaroxaban, or Apixaban versus Warfarin in Patients with Nonvalvular Atrial Fibrillation: A Systematic Review and Meta-Analysis of Subgroups. New oral anticoagulants (NOAC; rivaroxaban, dabigatran, apixaban) have become available as an alternative to warfarin anticoagulation in non-valvular atrial fibrillation (NVAF). The NOAC seem no more effective than warfarin for prevention of nonhemorrhagic stroke and SEE in the overall NVAF population, but are generally associated with a lower risk of ICB than warfarin.

FDA Approves New Anticlotting Drug. New factor Xa inhibitor has similar efficacy to warfarin with less bleeding risk, 2015.

Self-Monitoring while on the blood thinner
Self-monitoring by patients taking anti-clotting drugs such as warfarin is safe, effective and could lead to fewer deaths. Anticoagulants, or blood thinners, such as warfarin or coumadin, are a common treatment to prevent blood clots and strokes. Millions of people take the drugs but their reaction to the treatment must be tested regularly to prevent bleeding or hemorrhage. Patients who monitor their own treatment with a home testing kit and adjust their dose suffer fewer blood clots and deaths than people tested by medical professionals. Self-monitoring involves taking a blood sample from a pin prick and putting it into a home testing kit. The machine gives a reading that shows if the patient is in a safe range and not at risk of bleeding or having a blood clot, or if the dose needs to be adjusted. Monitoring is done almost daily in the early days of treatment and reduced over time to about once a month.

Risk of bleeding
Elevated blood concentrations of the soluble thrombomodulin antigen, a transmembrane glycoprotein expressed on the endothelial cell surface, are associated with an increased risk of bleeding during warfarin treatment. Arch Intern Med 2009;169:1210-1215.

Interactions with herbs and supplements questions
Q. Can you tell me if there are any contraindications between Passion Rx and warfarin (Coumadin)?
   A. We have not tested blood coagulation parameters with Passion Rx so we don't know if the herbs influence blood thinning or coagulation or have no effect. Most of the time Coumadin or warfarin is taken by those who have a heart condition or atrial fibrillation, and we do not suggest people with a heart condition take Passion Rx or most of the sex herbs.

Q. Are there any contraindications for lipoic acid being taken with warfarin? I have DVT and have been on the blood thinner for 3 months.
   A. We have not come across such interaction between warfarin and lipoic acid at this time, but we are not aware of any testing that has been done with these two together.

Q. My question is does taking reishi capsules interfere with the warfarin? I take 5mg a day.
   A. We checked Medline for the keywords reishi in association with warfarin, bleeding, platelet, clotting, Coumadin, and could not find any research.

Q. Is saw palmetto (serenoa repens) okay to take with warfarin? What about serrapeptase?
   A. Probably, but I have not seen such research regarding serenoa repens. As to serrapeptase, I would hold off using it with warfarin for now till I see some human trials.

Q. Can warfarin be taken the same day as an ahcc supplement?
   A. We have not seen any studies with this combination, so it is difficult to say for sure.

Q. Is Mind Power Rx a blood thinner? I am on warfarin at this time.
   A. We have not done coagulation blood studies with Mind Power Rx do determine whether it has any influence on blood coagulation or how it would interact with warfarin. There are a dozen nutrients and herbs in this product in small quantities each, and we don't know how this combination influences clotting or platelet aggregation. Many people just take Mind Power Rx one capsule two or three days a week, and it is unlikely that this would have much of an influence on clotting but we can't be 100 percent sure.

In July of 2006 I under-went valve replacement open heart surgery. In the opinion of my cardiologist warfarin sodium is the ONLY blood thinning agent which works. Everything else is a waste of money. I personally don't accept this premise as I don't believe in absolutes. While I am taking the warfarin presently my goal is to replace this substance with a natural/organic alternative. This may be a combination of foods and supplements. The challenge is in finding unbiased research.
    There is no simple answer. Some of the supplements listed at the top of this page may be helpful, but we suggest consultation with a health expert familiar with your condition and natural warfarin alternatives.

I use CoQ10 100 mg daily 5 days a week. I have noticed a lot of improvement in my energy and general condition of my health despite my age ( I am 76). My wife who is 70 has been using also CoQ10 50 mg with reasonably fair results. However, a year ago she had a stroke and she had immediate treatment in hospital, which saved her life. Now she almost recovered. She has to take every day one tablet of warfarin 3 mg for coagulation purposes for the stroke together with several other medicines for high blood pressure (Ezetrol, Exforge, Avernol and flutex) and Crestor for high cholesterol. She was told by another user of CoQ10 that he had read on some instructions on the CoQ10 package that if you are treated with warfarin then you should not use CoQ10. Kindly let me have your view on the matter and in particular if you would also advise that she should not take CoQ10 together with warfarin.
    In a rat study, coenzyme Q10 CoQ10 treatment accelerated metabolism of warfarin which would result in reduced activity. However, a human study did not find coq10 supplements to have an effect on activity.

I was recently put on warfarin (around 6 mg per day) due to blood clot in a vein in my leg (where I had a cast for broken ankle/leg). My medical nutritionist put me on Vitalzyme Xe (made by World Nutrition Inc) for somewhat high fibrinogen levels after I had been diagnosed with uterine leiomyosarcoma cancer in 2010. (PET/CT recently shows no cancer) The fibrinogen level went down to 352 a couple months ago. Iím taking 3 Vitalzyme Xe a day even while now on the blood thinner for past 3 weeks. Should I stop taking Vitalzyme Xe since Iím now on warfarin?
   I have no idea how effective this product is for blood thinning since I have not seen human studies regarding its effect on blood thinning.