Dexamethasone- This is a widely used anti-nausea drug  and recently studies have shown that it may interfere with cancer chemotherapy. It is a synthetic steroid--is routinely given to women just before they receive chemotherapy with either paclitaxel or doxorubicin, two drugs commonly used to treat breast cancer. In this laboratory study, the researchers show that pretreatment with dexamethasone reduces the ability of paclitaxel and doxorubicin to kill cancer cells.

Mixed or Uncertain Interaction with Tamoxifen

Soy   The use of dietary isoflavone supplements by postmenopausal women with breast cancer is increasing. Studies to determine whether genistein and daidzein, (the major phytoestrogens in soy), can stimulate breast cancer growth have been done and the results are conflicting in many cases.

Genistein and daidzein at low concentrations were found to stimulate breast tumor growth in in vitro and in vivo animal studies, and antagonize the antitumor effect of tamoxifen in vitro.

At high concentrations, genistein inhibited tumor growth and enhanced the effect of tamoxifen in vitro.

CONCLUSIONS: Genistein and daidzein may stimulate existing breast tumor growth and antagonize the effects of tamoxifen. Women with current or past breast cancer should be aware of the risks of potential tumor growth when taking soy products and they should be used in moderation and in fermented form (miso, Tempeh). What you don't want to do is take soy tablets or capsules that contain isoflavones or genestein. These purified forms of soy are not the same as soy, and they appear to do more harm than good.

PLEASE CONSULT WITH YOUR DOCTOR- If you are undergoing cancer treatments, or taking Tamoxifen or other hormonal blockers, any supplements you take should only be taken under the supervision of your doctor.

Herbal supplements and surgery: What you need to know
When you're preparing for surgery, your doctor typically asks you a number of questions about your health. Your surgeon and anesthesiologist use this information to help make your surgery as successful and safe as possible. One of the things your doctor wants to know is what, if any, medications you're currently taking. You may even be asked to prepare a list of these as part of your surgery preparation. You might not think to tell your doctor about the echinacea you take to help fight off your colds, or the feverfew you use to prevent your migraines.

What you may not realize is that these and other herbal supplements can affect the success of your surgical procedure, just as conventional medicines can. Learn more about the possible surgical complications of herbal supplements and find out which herbs, in particular, are a concern.

Herbs and surgery: Possible complications

Possible surgical complications vary, depending on the herb you're taking. Some herbal supplements increase heart rate and cause or worsen high blood pressure. Others may alter the effectiveness of sedative anesthesia used during surgery or medications you need during or after surgery.

Some herbs may suppress your body's immune system, interfering with healing. Others may increase your immune functioning, which, if you're having transplant surgery, could increase the possibility of your body rejecting the transplant. Still other herbs may contribute to excessive bleeding by interfering with your blood's ability to clot.

Common herbs: How they affect surgery

Some common herbal supplements that may cause surgical complications include:

•  Danshen. May cause bleeding.
• Dong quai. May cause bleeding.
• Echinacea. May interfere with the effectiveness of immunosuppressant drugs given to prevent transplant rejection. May interfere with your body's immune functioning after surgery.
• Ephedra. In late December 2003, the Food and Drug Administration announced the ban of ephedra from the marketplace because of health concerns. Ephedra goes by many names, including ma huang, Herbal Ecstasy, Chinese ephedra, mahuanggen and ma huang root. Ephedra can cause serious cardiovascular problems, leading to increased heart rate, heart attack or stroke. Interaction with anesthesia can lead to an abnormal heartbeat. And if you're taking a monoamine oxidase inhibitor (MAOI) — a type of antidepressant medication — the interaction between ephedra and anesthesia may result in life-threatening high blood pressure and coma.
• Feverfew. May cause bleeding.
• Garlic. May cause bleeding or interfere with normal blood clotting.
• Ginkgo. May cause bleeding.
• Ginseng. May cause bleeding.
• Goldenseal. May cause or worsen high blood pressure.
• Kava. May enhance the sedative effects of anesthesia.
• Licorice. May increase blood pressure. Most licorice candy contains little or no herbal licorice, but check product ingredients ("licorice flavoring" is safer than "licorice extract," or "natural licorice") to be sure. Your doctor may recommend you avoid licorice in any form as you prepare for surgery.
• St. John's wort. Can increase or decrease the effect of some drugs used during and after surgery.
• Valerian. May interfere with the effects of anesthesia.

As doctors learn more about herbal supplements and their effects, other herbs may be added to the list of those causing concern. Ask your doctor about any herbal product you're taking, even if it's not on this list.

Protect yourself: Discontinue herbs before surgery