Herb-Drug-Vitamin Info

 


Published by Broadway Books - on sale April, 2007

Surgery & Herbs 
Can taking herbs make surgery more risky? Researchers from the Department of Anesthesia and Critical Care at the University of Chicago’s Pritzker School of Medicine examined this issue for an article published in the Journal of the American Medical Association in 2001. Their findings include:

  • American ginseng can trigger low blood sugar and increase the risk of bleeding, and should be discontinued at least 7 days prior to surgery.
  • Echinacea can decrease the effectiveness of immunosuppressant drugs used for organ transplants.
  • Garlic can increase the risk of bleeding and should be discontinued at least 7 days prior to surgery.
  • Ginkgo biloba can increase the risk of bleeding and should be discontinued at least 36 hours prior to surgery.
  • Kava can increase the effects of anesthetics and should be discontinued at least 24 hours before surgery.
  • St. John’s wort can alter the action of liver enzymes, potentially altering the actions of numerous drugs, and should be discontinued at least 5 days prior to surgery.
  • Valerian can increase the sedative effects of anesthetics.

    • Given this information, might it be a good idea for anesthesiologists to interview their surgical patients several weeks before surgery to find out what herbs they may be taking? And to make the appropriate recommendations well before the surgery begins?

    CITATION - Ang-Lee MK, Moss J, Yuan CS. Herbal medicines and perioperative care. JAMA 2001;286(2):208-16.
     

    Banana Juice Bad for Parkinson's Medicine?  
    Japanese researchers tested the effects of banana juice on the drug levodopa (Dopar, Larodopa), which is used for Parkinson’s disease. They found that giving banana juice – fresh banana mixed with water – along with levodopa reduces levels of the drug in the body. (This did not happen when the drug was given along with a commercial juice containing 10% banana juice.) The researchers noted that the interaction between fresh banana juice and levodopa may reduce levodopa bioavailability, or the amount of the medicine "available for action" in the body of Parkinson’s patients. A significant decrease in the drug’s bioavailability might cause treatment failure.

    CITATION - Ogo Y, Sunagane N, Ohta T, et al. Banana juice reduces bioavailability of levodopa preparation. Yakugaku Zasshi 2005;125(12):1009-11.
     

    Pumping Away the B12?
    A class of drugs called proton pump inhibitors are popular remedies for heartburn and other symptoms of gastroesophageal reflux disease, as well as for related conditions. These drugs, which include lansoprazole (Prevacid) and omeprazole (Prilosec), suppress the secretion of gastric acid.

    Reducing the amount of gastric acid helps with heartburn and related ailments, but it can cause a problem, for vitamin B12 cannot be absorbed unless there is enough acid present. What helps calm heartburn can harm your nutrient status.

    This may not be a problem if you take these medicines occasionally and eat a nutritious diet, but, as Rex Brown, Professor of Clinical Pharmacy at the University of Tennessee pointed out in his article titled "Drug-Nutrient Interactions:"

    " ...chronic use of these agents can significantly decease the absorption of vitamin B12. Although most healthy patients have ample stores of vitamin B12 that will last for several years, an inability to absorb this vitamin because of chronic mediation use will invariable result in vitamin deficiency and a macrocytic anemia with potential neurologic sequelae...Patients receiving long-term acid-suppression therapy with proton pump inhibitors should have their vitamin B12 concentration checked regularly."

    In other words, over the long haul these medicines can rob the body of B12, leading to a form of anemia and nerve damage, as well as deceased energy, shortness of breath, heart palpitations and other problems. To prevent this, physicians could monitor vitamin B12 levels in all their patients taking these drugs. Are they routinely doing so?

    CITATION - Brown RO, Dickerson RN. Drug-nutrient interactions. Am J Managed Care 1999;5(3):345-352.
     

    Lab Results May Be Altered by Supplements
    The possibility that supplements may interact with medicines is slowly seeping into the public’s consciousness. Unfortunately, many people – and an alarming number of physicians – are not fully aware of the potential for herbs and supplements to interfere with the results of laboratory tests.

    A paper published in the Archives of Pathology & Laboratory Medicine in 2006 looked at 25 years worth of published reports of such interactions. Among the findings were:

    • the Chinese medicine Chan Su, or Dan Shen, may trigger false readings on tests for digoxin levels. This happens because an ingredient in the Chinese remedy can interfere with substances used to conduct the test. Digoxin (Digitek, Lanoxin) is used to treat heart failure and irregular heartbeat.
    • Chaparral, germander and kava-kava can alter the results of liver function tests such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST)

    CITATION  - Dasgupta A, Bernard DW. Herbal remedies: effects on clinical laboratory tests. Arch Pathol Lab Med 2006;130(4):521-8.
     

    Can Salad Make Your Medicine Ineffective?
    Eruca sativa is a plant native to Asia and the Mediterranean. It’s used as a medicinal herb to improve the appetite and sexual abilities, cleanse the blood, and discharge phlegm. It’s also eaten in salads. The Italians cal it rucola, the Germans ackerrauka, and the Japanese kibana-suzushiro.

    The herb contains a number of nutrients, including vitamin K, which helps blood coagulate. Specifically, there are 130 micrograms of vitamin K per 100 gm of herb – that’s more than the RDA for the vitamin.

    Some have questioned whether the blood-coagulating actions of Eruca sativa might be harmful to people taking warfarin (Coumadin, Jantoven) or other drugs to thin the blood. In 2006, a case report was published in the Swiss Medical Weekly, describing what happened to a 52-year-old woman who had been on warfarin. Doctors determined that the warfarin she was taking was no longer doing it’s job. She was put in the hospitalized and her warfarin dose gradually increased. Still, the medicine was not keeping her blood thin. Finally the doctors figured out that she had been taking large daily doses of Eruca sativa every day. The vitamin K in the her was effectively "cancelling" the warfarin and leaving her at risk of suffering a serious or fatal blood clot or other ailment.

    The authors of this paper concluded that with an increase in the use of herbal treatments, there can be "life-threatening" complications when the wrong herbs and medicines are mixed.

    CITATION  - Goz M, Goz F, Cakir O, et al. Warfarin resistance: interaction between warfarin and Eruca Sativa L. Swiss Med Weekly 2006;126:327.
     

    Penny Wise, Health Foolish?
    A 1999 article published in the American Journal of Managed Care looked at the interactions between various drugs and nutrients. In the section on "Vitamin Deficiencies," the authors noted that the drug furosemide (Lasix) could deplete the body’s supply of thiamine (vitamin B1). Furosemide, which belongs to a class of drugs called loop diuretics, is used to treat heart failure, kidney or liver disease, and elevated blood pressure.

    The paper noted that "Thiamine deficiency has been reported in a small group of patients with congestive heart failure who were receiving chronic furosemide. The authors of this study found increased urinary excretion of thiamine in these patients, presumably leading to frank deficiency over time. Therapeutic doses of intravenous thiamine increased the [heart’s ability to pump blood] in 4 of 5 of these patients. ...Despite these findings, routine supplementation of thiamine for patients with congestive heart failure receiving loop diuretics cannot be recommended at this time because of cost considerations."

    Thiamine is not stored in the body, so you must consume an adequate amount every day. But is it possible to do that when a drug which might be taken every day for the rest of your life robs thiamine from your body?

    I don’t know how much it costs to give patients thiamine. But I believe it is fair to ask what is the cost of not giving them  thiamine to replace the vitamin that the drug takes away from the body.

    CITATION  - Brown RO, Dickerson RN. Drug-nutrient interactions. Am J Managed Care 1999;5(3):345-352.
     

    CAM versus Cancer - Are Doctors Telling You What You Need to Know?
    A team of researchers from the Netherlands, writing in the cancer journal Oncologist, noted that several complementary and alternative medicines (CAM) are "probably capable" of interacting with drugs used to treat cancer. These CAMs include beta-carotene, echinacea, garlic, ginseng, grapeseed extract, guggulsterone, hops, kava-kava, quercetin, vitamin E, and the traditional Chinese medicines Gan Cao and Wu Wei Zi. The researchers point out that more and more cancer patients are using CAM therapies along with anti-cancer medicines, leading to an unknown number of drug side effects. And since CAM therapies may cause the blood levels of the anti-cancer drugs to remain low – possibly too low to be effective – they may be contributing to or causing treatment failure in an unknown number of patients.

    Are oncologists asking all their patients about the CAM therapies they may be using before they prescribe anti-cancer drugs?

    CITATION  - Meijerman I, Beinjnen JH, Schellens JH. Herb-drug interactions in oncology; focus on mechanisms of induction. Oncologist 2006;11(7):742-52.
     

    OJ: Good for Astronauts, Bad for Atenolol?
    It’s long been know that grapefruit juice can interfere with the workings of several medicines. What about other citrus fruits? For a 2005 study published in the European Journal of Clinical Pharmacology, Finnish researchers examined the effects of orange juice on the drug atenolol (brand name Tenormin), which is used to treat elevated blood pressure and angina.

    For this study, 10 healthy volunteers drank either 200 mg orange juice or water three times a day for three days, and twice on the fourth day. On day three, they were also given 50 mg of atenolol plus 200 mg of orange juice or water. The amount of atenolol in their blood and urine was then measured for almost a day and a half.

    The results? Orange juice reduced the peak amount of atenolol in the blood by 49%. The researchers concluded that "orange juice moderately interferes with the gastrointestinal absorption of atenolol" They noted that this interference can have clinical significance, for it may have the effect of leaving some patients with a medicine "underdose."

    Are all physicians who prescribe atenolol and similar drugs warning their patients about this possible food-drug interaction?

    CITATION  - Lilja JJ, Raaska K, Neuvonen PJ. Effects of orange juice on the pharmacokinetics of atenolol.
     

    A High That Can Leave You Low
    The herb damiana is felt to be good for lifting the mood and increasing sexual desire. It’s also smoked to produce a "high."

    However, mixing damiana certain drugs for diabetes may cause blood sugar to drop, leaving you feeling low rather than high. Beware of mixing damiana with these medicines, without first checking with your physician:

    • acarbose (Precose, Prandase)
    • acetohexamide (None known)
    • chlorpropamide (Diabinese, Novo-Propamide)
    • gliclazide (Diamicron, Novo-Gliclazide)
    • glimepiride (Amaryl)
    • glipizide (Glucotrol)
    • glipizide and metformin (Metaglip)
    • gliquidone (Beglynor, Glurenorm)
    • glyburide (Micronase, DiaBeta)
    • glyburide and metformin (Glucovance)
    • insulin (Humulin, Novolin R)
    • metformin (Glucophage, Riomet)
    • miglitol (Glyset)
    • nateglinide (Starlix)
    • pioglitazone (Actos)
    • repaglinide (Prandin, GlucoNorm)
    • rosiglitazone (Avandia)
    • rosiglitazone and metformin (Avandamet)
    • tolazamide (Tolinase)
    • tolbutamide (Apo-Tolbutamide, Tol-Tab)
       

    Avoid Chromium-Drug Interactions
    The mineral chromium helps the body metabolize and store fats, protein and carbohydrates. We get chromium when eating meat, whole-grain products and other foods, and many people get supplemental chromium in their multi-mineral or other supplements.

    But are you getting as much of the mineral as you think you are? Various medicines used to treat heartburn, gastroesophageal reflux disease and/or ulcers – including cimetidine, famotidine, nizatidine, rantidine, omeprazole, lansoprazole, rabeprazole, pantoprazole, and esomeprazole – can interfere with the absorption of chromium, or increase its excretion in the feces, by changing the level of stomach acidity.

    And could the chromium you’re taking be interfering with your medicines? Or could the medicines be causing you to absorb more calcium than usual? A number of drugs can do these things to chromium, including beta-blockers such as atenolol (Tenormin) or propanolol (Inderal), various corticosteroids, insulin, and nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen (Advil, Motrin), indomethacin (Indocin), naproxen (Aleve, Anaprox), and piroxicam (Feldene).

    Chromium is vital to life. It’s in our foods and common supplements. But who is telling people about these potential problems?
     

    Numerous Cases of Herb-Drug Interactions
    Writing in the journal Drugs in 2005, researchers from the National University of Singapore explored potentially dangerous interactions between herbs and drugs. They found cases where:

    • mixing denshin with the blood thinner warfarin (Coumadin, Jantoven) triggered bleeding in people taking the drug for long-term blood-thinning therapy
    • mixing garlic with the HIV drug saquinavir (Fortovase, Invirase) lowered the maximum plasma concentration of drug
    • mixing ginkgo biloba with the antidepressant trazodone (Desyrel) triggered coma
    • St. John’s wort reduced blood levels of midazolam (Versed), used for surgical sedation; tacrolimus (Prograf, Protopic), used to suppress the immune system for organ transplants and severe dermatitis; amitriptyline, used for depression; and digoxin (Digitek, Lanoxin), used for heart failure and irregular heartbeat

    The authors of this study concluded that "Interactions between herbal medicines and prescribed drugs can occur and may lead to serious clinical consequences."

    Of course, this is not to say that people should not take herbs. Instead, doctors should ask their patients what herbs and other supplements they are taking before prescribing any medicines.

    CITATION  - Hu Z, Yang X, Ho PC, et al. Herb-drug interactions: a literature review. Drugs 2005;65(9):1239-82.
     

    Does Your Doctor Discuss Calcium-Drug Interactions With You?
    Calcium, the most abundant mineral in the human body, has many vital functions. Among other things, it is necessary for strong bones and teeth, muscle contraction, and the secretion of enzymes and hormones.

    But calcium, like many vital and helpful minerals, can interact with the medicines doctors prescribe. As the National Institutes of Health’s Office of Dietary Supplements points out:

    "Calcium supplements may decrease levels of the drug digoxin, a medication given to heart patients. The interaction between calcium and vitamin D supplements and digoxin may also increase the risk of hypercalcemia [low levels of calcium]. Calcium supplements also interact with fluoroquinolones (a class of antibiotics including ciprofloxacin), levothyroxine (thyroid hormone) used to treat thyroid deficiency, antibiotics in the tetracycline family, tiludronate disodium (a drug used to treat Paget's disease), and phenytoin (an anti-convulsant drug). In all of these cases, calcium supplements decrease the absorption of these drugs when the two are taken at the same time."

    Many postmenopausal women take calcium supplements to keep bones strong, and many more people get calcium from a multi-vitamin. Are their doctors discussing the possibility of calcium-drug interactions with them?
     

    Cranberry Juice and Warfarin Overdose?  
    The drug warfarin (Coumadin, Jantoven) is used to "thin the blood" and reduce the risk of heart attack and stroke. The herb cranberry, often in the form of cranberry juice, is popularly used to prevent and/or treat urinary tract infections. Unfortunately, there may be trouble when the two substances meet in the body.

    The United Kingdom’s Committee on Safety of Medicines has issued a warning against drinking cranberry juice while taking warfarin, noting that cranberry juice contains substances that inhibit the ability of the body to metabolize warfarin. This might cause, in effect, a warfarin "overdose" leading to excessive bleeding. Indeed, the Committee cited the case of a man on warfarin who developed internal fatal internal bleeding after he began drinking cranberry juice.

    The committee suggested it "would be prudent for patients taking warfarin to be advised to limit or avoid drinking cranberry juice."

    CITATION - "Possible interaction between warfarin and cranberry juice." Current Problems in Pharmacovigilance, Vol 29, Sept 2003, p8.
     

    Pharmacists Agree that Vitamins and Minerals Can Interact with Drugs
    Pharmacists from New York’s St. John’s University College of Pharmacy and Allied Health Professions looked at the interactions between drugs, vitamins and minerals for a 2007 article published in the journal U.S. Pharmacist. Their findings include:

    • Mixing vitamin A with isotretinoin (Accutane), used for acne, or with acitretin (Soriatane), used for psoriasis, increases the risk suffering from nausea, vomiting, blurred vision and other symptoms of drug toxicity.
    • Mixing vitamin B6 with levodopa (Dopar, Larodopa), used for Parkinson’s disease, may reduce the medicine’s effectiveness.
    • Mixing niacin with statin drugs, used to reduce cholesterol levels, could increase the risk of drug side effects.

    The authors of this article noted that "There are many different types of drug interactions with vitamins and minerals, ranging in severity and significance." Has your doctor discussed possible supplement-drug interactions with you?

    CITATION - Sulli MM, Ezzo DC. Drug interactions with vitamins and minerals. US Pharmacist 2007;32(1):42-55.
     

    St. John's Wort Interferes with Cancer Drug
    Imatinib (brand name Gleevec) is a powerful medicine used to treat a specific form of leukemia and certain gastrointestinal tumors. Like all drugs, it is metabolized ("chewed-up" or "processed") in the body by certain enzymes. This is normal and good, because you don’t want the medicine to remain in the body forever. However, the same enzymes that process imatinib may affected by certain herbs, including St. John’s wort.

    Some researchers have wondered if taking St. John’s wort could interfere with the way the body metabolizes imatinib.

    A study appearing in Clinical Pharmacology and Therapeutics in 2004 looked at this issue. Six men and six women, ranging in age from 20 to 51, participated in this study. One days 1 and 15 of the study they were given 400 mg imatinib. On days 4 through 17, they each received 900 mg of St. John’s wort (300 mg, 3 times a day).

    The researchers found that "St. John’s wort increases imatinib clearance." In other words, it speeds up the processing and "disarming" of the drug. This, in effect, reduces the amount of the drug in the body and may reduce it effectiveness, requiring a larger does of the medicine in order to make sure enough remains in the body to do the necessary job. The researchers suggested that "patients taking imatinib should avoid taking St. John’s wort."

    CITATION - Frye RF, Fitzgerald SM, Lagattuta TF, et al. Effect of St John’s wort on imatinib mesylate pharmacokinetics. Clin Pharmacol Ther 2004;76(4):323-9.
     

    Herb Can Hamper Drug-Thinning Medication
    A 2004 study published in the British Journal of Clinical Pharmacology looked at the effects of the herbs St. John’s wort and ginseng on the drug warfarin (brand name Coumadin, Jantoven). Warfarin is a "blood thinner" used to prevent and/or treat certain forms of blood clots.

    The 12 healthy men participating in this study were  pretreated with either:

    • St. John’s wort for 14 days,

    • ginseng for 7, or
    • nothing

    ... and then given 25 mg of warfarin. Those who had been given either of the herbs continued to receive them for another 7 days after receiving the drug.

    The researchers studied the men’s blood and concluded that St. John’s wort triggered "a significant reduction in the pharmacological effect" of warfarin. In other words, the herb reduced the effectiveness of the drug, which could be dangerous.

    Ginseng did not affect warfarin in this study.

    CITATION - 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(5):592-9.  
     

    Herbs Can Knock Cancer Drugs Out of the "Therapeutic Range"
    The drugs used to treat cancer are given in carefully calculated doses that have very narrow therapeutic ranges. This means that a little too much, or a little too little, of cancer drugs can have very harmful effects.

    Herbs can alter the way the body handles various medicines. A researcher from the National Cancer Institute, noting that 13 - 63% of cancer patients use herbal preparations, headed up a review of studies looking in to how herbs and cancer drugs interact in the body.

    The resulting review paper, published in the Journal of Clinical Oncology in 2004, reported that several popular herbs have "the potential to significantly modulate the activity of drug-metabolizing enzymes..." and/or a protein "drug transport" system in the body. In other words, these herbs can influence the way the body processes cancer drugs, possibly reducing or increasing the drug levels in the body. This might push the level of the drug out of the therapeutic range, leaving you with too little or too much - and either state could be dangerous.

    Herbs that may interfere with the way the body handles cancer drugs include garlic, echinacea, Panax ginseng, St. John’s wort and kava.

    CITATION - Sparreboom A, Cox MC, Acharya MR, et al. Herbal remedies in the United States: potential adverse interactions with anticancer agents. J Clin Oncol 2004;22(12):2489-503.
     

    Don't Ask, Don't Know?
    The National Institutes of Health reported today that older Americans are not discussing complementary and alternative medicine use with their doctors. In their press release, the NIH stated that "In spite of the high use of complementary and alternative medicine (CAM) among people age 50 or older, 69 percent of those who use CAM do not talk to their doctors about it..."

    Herbs, vitamins and other supplements are a big part of complementary and alternative medicine.  Older folks  tend to use more medicines than younger folk, which means they have a higher risk of suffering from a herb-drug or vitamin-drug interactions. But if they're not talking to their doctors about it, they'll never know that. And they won't know how to use herbs, vitamins and other supplements safely. 

    Why don't people tell their doctors what supplements they're taking? There are several reasons, including the fact that many doctors make it clear to their patients that they're not interested in supplements, that they don't want to hear about it. Given the fact that tens of millions of Americans use herbs, vitamins and other supplements, and knowing that over 300 medications interact with herbs and vitamins, isn't it time for physicians to learn about and advise their patients on the best and safest ways to use herbs, vitamins and other supplements?