• Warfarin

    Trade Names :

    • Coumadin
    Alfalfa —Possible Harmful Interaction Chondroitin —Possible Harmful Interaction Coenzyme Q10 (CoQ10) —Possible Harmful Interaction Cranberry —Possible Harmful Interaction Danshen —Harmful Interaction Devil's Claw —Possible Harmful Interaction Dong Quai —Possible Harmful Interaction Feverfew —Possible Harmful Interaction Garlic —Possible Harmful Interaction Ginger —Possible Harmful Interaction Ginkgo —Possible Harmful Interaction Ginseng —Possible Harmful Interaction Green Tea —Possible Harmful Interaction in Very High Doses Ipriflavone —Possible Harmful Interaction Papain, Bromelain —Possible Harmful Interaction PC-SPES —Possible Harmful Interaction Policosanol —Possible Harmful Interaction Reishi —Possible Harmful Interaction Royal Jelly —Possible Harmful Interaction Soy —Possible Harmful Interaction St. John's Wort —Possible Harmful Interaction Vinpocetine —Possible Harmful Interaction Vitamin A —Possible Harmful Interaction Vitamin C —Possible Harmful Interaction Vitamin E —Possible Harmful Interaction Vitamin K —Possible Harmful Interaction White Willow —Possible Harmful Interaction Other Herbs and Supplements —Possible Harmful Interaction
    Warfarin (Coumadin) is an anticoagulant used to thin the blood and prevent it from clotting. It is a somewhat dangerous drug that can be affected by many substances, including food. Note : If you are taking warfarin, we do not recommend taking any herb or supplement except on a physician's advice.
    Similar blood-thinning drugs are anisindione (Miradon) and dicumarol.
    The herb alfalfa (Medicago sativa) is promoted for a variety of conditions. The relatively high vitamin K content in alfalfa could reduce the effectiveness of warfarin. Vitamin K directly counteracts warfarin's blood-thinning effects. Since the amount of vitamin K in alfalfa varies widely, it is difficult to give an exact safe upper dose.
    As a precaution, avoid alfalfa supplements during warfarin therapy except under medical supervision.
    The herb chamomile contains substances in the coumarin family. Some coumarins have blood thinning actions that could interact with warfarin. One case report exists of a person in which it appears that combined use of chamomile and warfarin led to internal bleeding. 74
    Based on chondroitin’s chemical similarity to the anticoagulant drug heparin, it has been suggested that chondroitin might have anticoagulant effects as well. There are no case reports of any problems relating to this, and studies suggest that chondroitin has at most a mild anticoagulant effect. 62 Nonetheless, prudence suggests that chondroitin should not be combined with warfarin except under physician supervision.
    Coenzyme Q 10 (CoQ 10 )
    CoQ 10 is a vitamin-like substance that plays a fundamental role in the body's energy production. 2,3
    This substance is somewhat similar in structure to vitamin K, and reportedly it, too, can reduce the therapeutic effects of warfarin. 4 In three case reports, CoQ 10 was found to interfere with warfarin's blood-thinning effects. 5 A double-blind study found no interaction between CoQ 10 and warfarin. 59 However, in view of warfarin’s low margin of safety, prudence indicates physician supervision before combining CoQ 10 with warfarin.
    Several case reports suggest that cranberry juice can increase warfarin’s action, causing dangerous and potentially fatal bleeding problems. 65, 82 However, formal studies have failed to find evidence of such an interaction. 80, 81 Nonetheless, prudence would suggest continued caution at this time, especially when taking cranberry juice in dosages higher than 8 oz daily.
    The herb danshen, the root of Salvia miltiorrhiza, is used in traditional Chinese medicine for treating heart disease.
    Preliminary evidence, including several case reports, suggests that danshen can dangerously increase the effects of warfarin and cause significant bleeding problems. 6,7,8
    Therefore, if you take warfarin, you should avoid danshen except under a physician's supervision.
    Devil's Claw
    The herb devil's claw ( Harpogophytum procumbens ) is used for various types of arthritis and digestive problems.
    According to one case report, devil's claw might increase the risk of abnormal bleeding when taken with warfarin. 9
    As a precaution, you should probably not combine devil's claw and warfarin except under a physician's supervision.
    Dong Quai
    The herb dong quai ( Angelica sinensis ) is used for menstrual disorders.
    According to one case report, dong quai may add to the blood-thinning effects of warfarin, thus increasing the risk of abnormal bleeding. 10
    You should probably avoid combining dong quai and warfarin without medical supervision.
    The herb feverfew ( Tanacetum parthenium ) is primarily used for the prevention and treatment of migraine headaches.
    In vitro studies suggest that feverfew thins the blood by interfering with the ability of blood platelets to clump together. 11-14 This raises the concern that feverfew might increase the risk of abnormal bleeding when combined with warfarin. However, there is as yet no evidence that the blood-thinning effect of feverfew is significant in humans. 15
    Though an additive effect of feverfew and warfarin appears to be theoretical at this time, it may be best to avoid this combination except under medical supervision.
    The herb garlic (Allium sativum) is taken to lower cholesterol, among many other proposed uses.
    One of the possible side effects of garlic is an increased tendency to bleed. 16,17 This blood-thinning effect has been demonstrated in a double-blind trial of garlic in 60 volunteers, 18 as well as in other studies 19,20 and one case report. 21
    According to two other case reports, the blood-thinning effects of warfarin were greatly enhanced in individuals taking garlic. 22 This could amplify the risk of bleeding problems.
    Based on these findings, you should avoid combining garlic and warfarin except under a physician's supervision.
    The herb ginger ( Zingiber officinale ) is used for nausea associated with motion sickness, morning sickness in pregnancy, and the postsurgical period.
    Ginger appears to thin the blood by interfering with the ability of blood platelets to clump together. 23,24 As with feverfew, this raises the concern that ginger might increase the risk of abnormal bleeding when taken with warfarin. However, there is no evidence at present that the blood-thinning effect of ginger is significant in humans. 25,26,27
    Though an additive effect of ginger and warfarin appears to be theoretical based on current evidence, it may be best to avoid this combination except under medical supervision. Ginger flavored drinks should not present a problem, but candies containing whole dried ginger are potentially of concern.
    The herb ginkgo ( Ginkgo biloba ) has been used to treat Alzheimer's disease and ordinary age-related memory loss, among many other uses.
    Inconsistent evidence suggests that ginkgo might reduce the ability of platelets (blood-clotting cells) to stick together. 28,66,67,68,76 In addition, several case reports suggest that use of ginkgo may be associated with an increased risk of serious abnormal bleeding episodes in individuals taking the herb. 29,30,31,69,70 These findings raise concern that ginkgo might add to the blood-thinning effects of warfarin, and there is one report of abnormal bleeding in an individual who had been taking the herb and drug together. 32 However, two double-blind studies found no interaction between ginkgo and warfarin. 59,77 These findings are reassuring. Nonetheless, in view of warfarin’s low margin of safety, prudence indicates physician supervision before combining ginkgo with warfarin.
    The herb ginseng ( Panax ginseng ) is promoted as an adaptogen , a treatment that is said to help the body adapt to stress of all types.
    A case report suggests that Panax ginseng can reduce the anticoagulant effects of warfarin; 1 however, 3 double-blind studies failed to find any interaction. 64,79,85 In general, double-blind studies are far more reliable than case reports, and, therefore, it would appear that there is not too much reason for concern regarding this potential interaction. However, another double-blind trial that evaluated the closely related American ginseng species ( Panax quinquefolius ) found that use of the herb reduced the anticoagulant effects of warfarin, similarly to what was seen in the case report. 63 At this point, therefore, it is reasonable to suggest that caution should be exercised when combining ginseng and warfarin.
    Low Carb, High Protein Diet
    Low carbohydrate, high-protein diets have been advocated for weight loss. According to two case reports, adoption of such diets may decrease the effectiveness of warfarin, possibly by increasing blood levels of a substance called albumin that might tend to bind and inactivate warfarin in the body. 73
    Green Tea
    Dried green tea leaf contains significant levels of vitamin K on a per-weight basis. On this basis, it has been stated that people using blood thinners in the warfarin family should avoid green tea. However, green tea taken as a beverage provides such small amounts of the vitamin that the risk seems minimal for normal consumption. There is one case report of problems that developed in a person on warfarin who consumed as much as a gallon of green tea daily. 33
    Ipriflavone, a synthetic isoflavone that slows bone breakdown, is used to treat osteoporosis.
    Warfarin use increases the risk of osteoporosis. Because ipriflavone has been found to help prevent osteoporosis in certain circumstances, you might be tempted to consider taking this supplement while you use warfarin. However, some evidence indicates that ipriflavone might interfere with the body's normal breakdown of warfarin. 34 This could raise the levels of warfarin in your body and increase the risk of abnormal bleeding.
    If you try this combination, you need to do so under physician supervision.
    Papain, Bromelain
    One case report suggests that papain, a digestive enzyme found in papaya extract ( Carica papaya ), might add to warfarin's blood-thinning effect. 35
    The substance vinpocetine is sold as a dietary supplement for the treatment of age-related memory loss and impaired mental function. Vinpocetine is thought to inhibit blood platelets from forming clots. 60 For this reason, it should not be combined with medications or natural substances that impair the blood’s ability to clot normally, as this may lead to excessive bleeding. One study found only a minimal interaction between the blood-thinning drug warfarin and vinpocetine (and it actually involved an increased tendency for blood clotting), but prudence dictates caution anyway. 44
    PC-SPES is an herbal combination that has shown promise for the treatment of prostate cancer. One case report suggests that PC-SPES might increase risk of bleeding complications if combined with blood-thinning medications. 56 Subsequent evidence has indicated that PC-SPES actually contains warfarin, making this interaction inevitable. 61
    Policosanol, derived from sugarcane, is used to reduce cholesterol levels. It also interferes with platelet clumping, creating a risk of interactions with blood-thinning drugs.
    For example, a 30-day, double-blind, placebo-controlled trial of 27 individuals with high cholesterol levels found that policosanol at 10 mg daily markedly reduced the ability of blood platelets to clump together. 37 Another double-blind, placebo-controlled study of 37 healthy volunteers found evidence that the blood-thinning effect of policosanol increased as the dose was increased—the larger the policosanol dose, the greater the effect. 38 Yet another double-blind, placebo-controlled study of 43 healthy volunteers compared the effects of policosanol (20 mg daily), the blood-thinner aspirin (100 mg daily), and policosanol and aspirin combined at these same doses. 39 The results again showed that policosanol substantially reduced the ability of blood platelets to stick together, and that the combined therapy exhibited additive effects.
    Based on these findings, you should not combine warfarin and policosanol except under medical supervision.
    One study suggests that reishi impairs platelet clumping. 58 This creates the potential for an interaction with any blood-thinning medication.
    One case report indicates that use of royal jelly can increase the effectiveness of warfarin, creating risk of bleeding. 83
    One case report indicates that soy milk might decrease warfarin’s effectiveness. 71
    St. John's Wort
    The herb St. John's wort ( Hypericum perforatum ) is primarily used to treat mild to moderate depression.
    Evidence suggests that St. John's wort may interfere with warfarin, possibly requiring an increased dosage of the drug to maintain the proper therapeutic effect. 40,41,42,72 Seven cases have been reported in which the blood-thinning effects of warfarin have been impaired in individuals taking St. John's wort. 43
    A "hidden" risk lies in this type of interaction. Suppose your physician has raised the warfarin dose to take into account the effect of St. John's wort in holding down drug levels. If you then stop taking the herbal product, it would be like releasing the brakes, and your warfarin levels could surge dangerously high.
    For these reasons, if you take warfarin, avoid St. John's wort except under a physician's supervision.
    Vitamin A
    Supplemental vitamin A might increase the blood-thinning effects of warfarin, and this could potentially lead to an increased risk of abnormal bleeding. 45
    For this reason, it may be best to avoid combining vitamin A with warfarin unless supervised by a physician.
    Vitamin C
    Vitamin C taken in high dosages (more than 1,000 mg daily) has been reported to reduce the blood-thinning effect of warfarin. 46-49 In one case, the person was taking 1,000 mg of vitamin C daily; another involved huge megadoses (about 16,000 mg daily).
    As a precaution, if you take warfarin, consult with your physician before taking high-dose vitamin C supplements.
    Vitamin E
    On the basis that vitamin E "thins" the blood, 50 it has been suggested not to combine vitamin E with warfarin. However, a 4-week, double-blind study of 25 individuals taking warfarin found no additive effect. 51 None of the participants taking vitamin E at a daily dose of 800 or 1,200 IU showed an increased risk for abnormal bleeding.
    In contrast, a case report indicated that vitamin E (800 IU daily) added to the effects of warfarin and resulted in abnormal bleeding. 52 Because this effect did not become apparent until the fourth week, it is possible that problems might take longer to develop than the 4-week period covered by the double-blind study, or that certain individuals might be more prone to an interaction. An unpublished, 30-day study of three volunteers taking a warfarin-like drug also found an additive effect with only 42 IU of vitamin E daily. 53
    Though the evidence supporting a possible interaction is scanty, it is best not to risk serious bleeding problems. Avoid combining vitamin E with warfarin except under the supervision of a physician.
    Vitamin K
    Vitamin K is an antidote to warfarin—it directly counteracts warfarin's blood-thinning effects. This is true for both supplemental vitamin K and foods high in vitamin K. For this reason, eating more vitamin K-rich vegetables can decrease warfarin's therapeutic effect, and eating less of these foods can increase the drug's effect. 54,55 Either situation can lead to potential life-threatening complications.
    Therefore, once you are established on a certain dose of warfarin, you should not change your usual intake of vitamin K without informing your physician.
    One study suggests a novel way of using this effect deliberately. 84 Researchers gave people on warfarin a fixed daily dose of vitamin K in order to override the changes in warfarin action caused by the natural variation in day-to-day dietary vitamin K consumption. The results were positive: INR values—the standard measurement of warfarin’s blood thinning effect—became more stable. Needless to say, however, this method should not be used except under close physician supervision.
    White Willow
    The herb white willow ( Salix alba ), also known as willow bark, is used to treat pain and fever. White willow contains a substance that is converted by the body into a salicylate similar to the blood-thinner aspirin.
    Because white willow, like aspirin, may enhance the blood-thinning effects of warfarin, this combination should be avoided unless medically supervised.
    One case report suggests that a combination of the herbs boldo and fenugreek increased the effects of warfarin. 57 Another isolated case report suggests that the same can happen when fish oil is combined with warfarin. 78
    Based on their known effects or the effects of their constituents, the following herbs and supplements might not be safe to combine with warfarin, though this has not been proven: chamomile ( Matricaria recutita ), Coleus forskohlii , ginger ( Zingiber officinale ), horse chestnut ( Aesculus hippocastanum ), papaya ( Carica papaya ), red clover ( Trifolium pratense ), and reishi ( Ganoderma lucidum ); mesoglycan , fish oil , oligomeric proanthocyanidins (OPCs), and phosphatidylserine .


    1 Janetzky K, Morreale AP. Probable interaction between warfarin and ginseng. Am J Health Syst Pharm. 1997;54:692-693.

    2 Mortensen SA, Leth A, Agner E, et al. Dose-related decrease of serum coenzyme Q 10 during treatment with HMG-CoA reductase inhibitors. Mol Aspects Med. 1997;18(suppl):S137-S144.

    3 Ghirlanda G, Oradei A, Manto A, et al. Evidence of plasma CoQ 10 -lowering effect by HMG-CoA reductase inhibitors: a double-blind, placebo-controlled study. J Clin Pharmacol. 1993;33:226-229.

    4 Combs AB, Porter TH, Folkers K. Anticoagulant activity of a naphtoquinone analog of vitamin K and an inhibitor of coenzyme Q 10 -enzyme systems. Res Commun Chem Pathol Pharmacol. 1976;13:109-114.

    5 Spigset O. Reduced effect of warfarin caused by ubidecarenone [letter]. Lancet. 1994;344:1372-1373.

    6 Lo ACT, Chan K, Yeung JHK, et al. The effects of Danshen (Salvia miltorrhiza) on pharmacokinetics and pharmacodynamics of warfarin in rats. Eur J Drug Metab Pharmacokinet. 1992;17:257-262.

    7 Brinker F. Herb Contraindications and Drug Interactions: With Appendices Addressing Specific Conditions and Medicines. 2nd ed. Sandy, OR: Eclectic Medical Publications; 1998.

    8 Chan TY. Interaction between warfarin and danshen (Salvia miltiorrhiza) . Ann Pharmacother. 2001;35:501-504.

    9 Shaw D, Leon C, Kolev S, et al. Traditional remedies and food supplements. A 5-year toxicological study (1991-1995). Drug Saf. 1997;17:342-356.

    10 Page RL II, Lawrence JD. Potentiation of warfarin by dong quai. Pharmacotherapy. 1999;19:870-876.

    11 Heptinstall S, Groenewegen WA, Spangenberg P, et al. Extracts of feverfew may inhibit platelet behavior via neutralization of sulphydryl groups. J Pharm Pharmacol. 1987;39:459-465.

    12 Makheja AN, Bailey JM. The active principle in feverfew [letter]. Lancet. 1981;2:1054.

    13 Sumner H, Salan U, Knight DW, et al. Inhibition of 5-lipoxygenase and cyclo-oxygenase in leukocytes by feverfew. Involvement of sesquiterpene lactones and other components. Biochem Pharmacol. 1992;43:2313-2320.

    14 Groenewegen WA, Heptinstall S. A comparison of the effects of an extract of feverfew and parthenolide, a component of feverfew, on human platelet activity in-vitro. J Pharm Pharmacol. 1990;42:553-557.

    15 Biggs MJ, Johnson ES, Persaud NP, et al. Platelet aggregation in patients using feverfew for migraine [letter]. Lancet. 1982;2:776.

    16 Gadkari JV, Joshi VD. Effect of ingestion of raw garlic on serum cholesterol level, clotting time and fibrinolytic activity in normal subjects. J Postgrad Med. 1991;37:128-131.

    17 Burnham BE. Garlic as a possible risk for postoperative bleeding. Plast Reconstr Surg. 1995;95:213.

    18 Kiesewetter H, Jung F, Jung EM, et al. Effect of garlic on platelet aggregation in patients with increased risk of juvenile ischemic attack. Eur J Clin Pharmacol. 1993;45:333-336.

    19 [No authors listed]. The effect of essential oil of garlic on hyperlipemia and platelet aggregation—an analysis of 308 cases. Cooperative Group for Essential Oil of Garlic. J Tradit Chin Med. 1986;6:117-120.

    20 Bordia A. Effect of garlic on human platelet aggregation in vitro. Atherosclerosis. 1978;30:355-360.

    21 Rose KD, Croissant PD, Parliament CF, et al. Spontaneous spinal epidural hematoma with associated platelet dysfunction from excessive garlic ingestion: a case report. Neurosurgery. 1990;26:880-882.

    22 Sunter WH. Warfarin and garlic. Pharm J. 1991;246:722.

    23 Backon J. Ginger: inhibition of thromboxane synthetase and stimulation of prostacyclin: relevance for medicine and psychiatry. Med Hypotheses. 1986;20:271-278.

    24 Srivastava KC. Aqueous extracts of onion, garlic and ginger inhibit platelet aggregation and alter arachidonic acid metabolism. Biomed Biochim Acta. 1984;43:S335-S346.

    25 Bordia A, Verma SK, Srivastava KC. Effect of ginger ( Zingiber officinale Rosc.) and fenugreek ( Trigonella foenumgraecum L. ) on blood lipids, blood sugar and platelet aggregation in patients with coronary artery disease. Prostaglandins Leukot Essent Fatty Acids. 1997;56:379-384.

    26 Janssen PL, Meyboom S, van Staveren WA, et al. Consumption of ginger (Zingiber officinale roscoe) does not affect ex vivo platelet thromboxane production in humans. Eur J Clin Nutr. 1996;50:772-774.

    27 Lumb AB. Effect of dried ginger on human platelet function. Thromb Haemost. 1994;71:110-111.

    28 Chung KF, Dent G, McCusker M, et al. Effect of a ginkgolide mixture (BN 52063) in antagonising skin and platelet responses to platelet activating factor in man. Lancet. 1987;1:248-251.

    29 Rosenblatt M, Mindel J. Spontaneous hyphema associated with ingestion of Ginkgo biloba extract [letter]. N Engl J Med. 1997;336:1108.

    30 Rowin J, Lewis SL. Spontaneous bilateral subdural hematomas with chronic Ginkgo biloba ingestion. Neurology. 1996;46:1775-1776.

    31 Vale S. Subarachnoid hemorrhage associated with Ginkgo biloba [letter]. Lancet. 1998;352:36.

    32 Matthews MK Jr. Association of Ginkgo biloba with intracerebral hemorrhage. Neurology. 1998;50:1933-1934.

    33 Taylor JR, Wilt VM. Probable antagonism of warfarin by green tea. Ann Pharmacother. 1999;33:426-428.

    34 Monostory K, Vereczkey L, Levai F, et al. Ipriflavone as an inhibitor of human cytochrome P450 enzymes. Br J Pharmacol. 1998;123:605-610.

    35 Shaw D, Leon C, Kolev S, et al. Traditional remedies and food supplements. A 5-year toxicological study (1991-1995). Drug Saf. 1997;17:342-356.

    36 Arruzazabala ML, Mas R, Molina V, et al. Effect of policosanol on platelet aggregation in type II hypercholesterolemic patients. Int J Tissue React. 1998;20:119-124.

    37 Arruzazabala ML, Mas R, Molina V, et al. Effect of policosanol on platelet aggregation in type II hypercholesterolemic patients. Int J Tissue React. 1998;20:119-124.

    38 Arruzazabala ML, Valdes S, Mas R, et al. Effect of policosanol successive dose increases on platelet aggregation in healthy volunteers. Pharmacol Res. 1996;34:181-185.

    39 Arruzazabala ML, Valdes S, Mas R, et al. Comparative study of policosanol, aspirin and the combination therapy policosanol-aspirin on platelet aggregation in healthy volunteers. Pharmacol Res. 1997;36:293-297.

    40 Maurer A. Interaction of St. John's wort extract with phenprocoumon. Eur J Clin Pharmacol. 1999;55:A22.

    41 Jobst KA, McIntyre M, St. George D, et al. Safety of St. John's wort (Hypericum perforatum) . Lancet. 2000:355:575.

    42 Johne A, Brockmuller J, Bauer S, et al. Pharmacokinetic interaction of digoxin with an herbal extract from St. John's wort (Hypericum perforatum) . Clin Pharmacol Ther. 1999;66:338-345.

    43 Yue QY, Bergquist C, Gerden B. Safety of St. John's wort [letter]. Lancet. 2000;355:576-577.

    44 Hitzenberger G, Sommer W, Grandt R. Influence of vinpocetine on warfarin-induced inhibition of coagulation. Int J Clin Pharmacol Ther Toxicol. 1990;28:323-328.

    45 Harris JE. Interaction of dietary factors with oral anticoagulants: review and applications. J Am Dietet Assoc. 1995;95:580-584.

    46 Harris JE. Interaction of dietary factors with oral anticoagulants: review and applications. J Am Dietet Assoc. 1995;95:580-584.

    47 Schrogie JJ. Letter: Coagulopathy and fat-soluble vitamins. JAMA. 1975;232:19.

    48 Rosenthal G. Interaction of ascorbic acid and warfarin [letter]. JAMA. 1971;215:1671.

    49 Smith EC, Skalski RJ, Johnson GC, et al. Interaction of ascorbic acid and warfarin [letter]. JAMA. 1972;221:1166.

    50 White JG, Rao GH, Gerrard JM. Effects of nitroblue tetrazolium and vitamin E on platelet ultrastructure, aggregation, and secretion. Am J Pathol. 1977;88:387-402.

    51 Kim JM, White RH. Effect of vitamin E on the anticoagulant response to warfarin. Am J Cardiol. 1996;77:545-546.

    52 Corrigan J, Marcus FI. Coagulopathy associated with vitamin E ingestion. JAMA. 1974;230:1300-1301.

    53 Schrogie JJ. Letter: Coagulopathy and fat-soluble vitamins. JAMA. 1975;232:19.

    54 Pedersen FM, Hamberg O, Hess K, et al. The effect of dietary vitamin K on warfarin-induced anticoagulation. J Intern Med. 1991;229:517-520.

    55 Chow WH, Chow TC, Tse TM, et al. Anticoagulation instability with life-threatening complication after dietary modification. Postgrad Med J. 1990;66:855-857.

    56 Weinrobe MC, Montgomery B. Acquired bleeding diathesis in a patient taking PC-SPES [letter]. N Engl J Med. 2001;345:1213-1214.

    57 Lambert JP, Cormier A. Potential interaction between warfarin and boldo-fenugreek. Pharmacotherapy. 2001;21:509-512.

    58 Su C, Shiao M, Wang C. Potentiation of ganodermic acid S on prostaglandin E(1)-induced cyclic AMP elevation in human platelets. Thromb Res. 2000;99:135-145.

    59 Engelsen J, Nielsen JD, Winther K. Effect of coenzyme Q10 and Ginkgo biloba on warfarin dosage in stable, long-term warfarin treated outpatients. A randomised, double blind, placebo-crossover trial. Thromb Haemost. 2002;87:1075-1076.

    60 Kiss B, Karpati E. Mechanism of action of vinpocetine [in Hungarian; English abstract]. Acta Pharm Hung. 1996;66:213-214.

    61Sovak M, Seligson AL, Konas M, et al. PC-SPES in prostate cancer: an herbal mixture currently containing warfarin and previously diethylstilbestrol and indomethacin. Presented at: 93rd Annual Meeting of the American Association for Cancer Research; April 6-10, 2002; San Francisco, CA.

    62 AbdelFattah W, Hammad T. Chondroitin sulfate and glucosamine: A review of their safety profile. JANA 2001;3:16-23.

    63 Yuan CS, Wei G, Dey L, et al. American ginseng reduces warfarin's effect in healthy patients. Ann Intern Med. 2004;141:23-27.

    64 Jiang X, Williams KM, Liauw WS, et al. Effect of St John's wort and ginseng on the pharmacokinetics and pharmacodynamics of warfarin in healthy subjects. Br J Clin Pharmacol. 2004;57:592-599.

    65 Committee on Safety of Medicines. Possible interaction between warfarin and cranberry juice. Current Problems in Pharmacovigilance. 2003;29:8.

    66 Kohler S, Funk P, Kieser M. Influence of a 7-day treatment with Ginkgo biloba special extract EGb 761 on bleeding time and coagulation: a randomized, placebo-controlled, double-blind study in healthy volunteers. Blood Coagul Fibrinolysis. 2004;15:303-309.

    67 Kudolo GB, Dorsey S, Blodgett J. Effect of the ingestion of Ginkgo biloba extract on platelet aggregation and urinary prostanoid excretion in healthy and Type 2 diabetic subjects. Thromb Res. 2002;108:151-160.

    68 Bal Dit Sollier C, Caplain H, Drouet L. No alteration in platelet function or coagulation induced by EGb761 in a controlled study. Clin Lab Haematol. 2003;25:251-253.

    69 Hauser D, Gayowski T, Singh N. Bleeding complications precipitated by unrecognized Gingko biloba use after liver transplantation. Transpl Int. 2002;15:377-379. Epub 2002 Jun 19.

    70 Fong KC, Kinnear PE. Retrobulbar haemorrhage associated with chronic Gingko biloba ingestion. Postgrad Med J. 2003;79:531-532.

    71 Cambria-Kiely JA. Effect of soy milk on warfarin efficacy. Ann Pharmacother. 2002;36:1893-1896.

    72 Jiang X, Williams KM, Liauw WS, et al. Effect of St John's wort and ginseng on the pharmacokinetics and pharmacodynamics of warfarin in healthy subjects. Br J Clin Pharmacol. 2004;57:592-599.

    73 Beatty SJ, Mehta BH, Rodis JL. Decreased warfarin effect after initiation of high-protein, low-carbohydrate diets. Ann Pharmacother. 2005;39:744-747.

    74 Segal R, Pilote L. Warfarin interaction with Matricaria chamomilla. CMAJ. 2006;174:1281-1282.

    75 Greenblatt DJ, von Moltke LL, Perloff ES, et al. Interaction of flurbiprofen with cranberry juice, grape juice, tea, and fluconazole: In vitro and clinical studies. Clin Pharmacol Ther. 2006;79:125-133.

    76 Kudolo GB, Wang W, Barrientos J, et al. The ingestion of gingko biloba extract (EGb 761) inhibits arachidonic acid-mediated platelet aggregation and thromboxane B 2 production in healthy volunteers. J Herb Pharmacother. 2005;4:13-26.

    77 Jiang X, Williams KM, Liauw WS, et al. Effect of ginkgo and ginger on the pharmacokinetics and pharmacodynamics of warfarin in healthy subjects. Br J Clin Pharmacol. 2005;59:425-432.

    78 Buckley MS, Goff AD, Knapp WE, et al. Fish oil interaction with warfarin. Ann Pharmacother. 2004;38:50-52.

    79 Jiang X, Williams KM, Liauw WS, et al. Effect of ginkgo and ginger on the pharmacokinetics and pharmacodynamics of warfarin in healthy subjects. Br J Clin Pharmacol. 2005;59:425-432.

    80 Li Z, Seeram NP, Carpenter CL, et al. Cranberry does not affect prothrombin time in male subjects on warfarin. J Am Diet Assoc. 2006;106:2057-2061.

    81 Pham DQ, Pham AQ. Interaction potential between cranberry juice and warfarin. Am J Health Syst Pharm. 2007;64:490-494.

    82 Welch JM, Forster K. Probable elevation in international normalized ratio from cranberry juice. J Pharm Technol. 2007;23:104-107.

    83 Lee NJ, Fermo JD. Warfarin and royal jelly interaction. Pharmacotherapy. 2006;26:583-586.

    84 Rombouts EK, Rosendaal FR, van der Meer FJ. Daily vitamin K supplementation improves anticoagulant stability. J Thromb Haemost. 2007 Jul 31. [Epub ahead of print]

    85 Lee SH, Ahn YM, Ahn SY, et al. Interaction between warfarin and Panax ginseng in ischemic stroke patients. J Altern Complement Med. 2008 Jul 20.

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  • Ideal Body Weight

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    Using body mass index as a reference, this calculator determines your ideal body weight range. All you need to do is enter your height.

  • Body Mass Index

    Body Mass IndexLearn more

    This tool considers your height and weight to assess your weight status.

  • Can we help answer your questions?

    Wellmont Nurse Connection is your resource for valuable health information any time, 24 hours a day, seven days a week. Speak to a Nurse any time, day or night, at (423) 723-6877 or toll-free at 1-877-230-NURSE.