Undergoing treatment for cancer is difficult enough, but navigating nutritional options during and after treatment can also be daunting.

To help survivors better understand how vitamins, herbal supplements and over-the-counter medications interact with common cancer drugs, Stephen Farley spoke at a meeting of the Breast Cancer Survivors Support Group Dec. 4 at Wilton Library.

Farley is a hematology and oncology pharmacist at Norwalk Hospital's Whittingham Cancer Center. He evaluates chemotherapy treatments, medications, and supplements to make sure they don’t adversely affect chemo, other medications or the disease itself.

To help navigate herbal options, he highly recommended an app called About Herbs, run by Memorial Sloan Kettering Cancer Center, as a point of reference. The app offers information about herbal products and how they can interact with medications.

“A lot of package inserts won’t give you a lot of interaction information when it comes to over-the-counter products or supplements,” he said. “Whenever you approach a supplement, look at the contents and the percentages [of recommended daily dosages],” he said.

Farley offered handouts to the women attending the meeting based on whether they were taking tamoxifen or aromatase inhibitors for continued treatment of hormone-positive breast cancer.

Aromatase inhibitors block the enzyme aromatase, which converts other hormones into estrogen in the body. The result is less estrogen is available to stimulate the growth of breast cancer cells that feed on estrogen

Thus, substances containing estrogen, such as the steroid estradiol, or phyto-estrogens found in certain plants, should be avoided while taking an aromatase inhibitor because they could reduce the drug’s effectiveness. Certain medications should be used with caution because of an increased risk of side effects caused when used with an aromatase inhibitor. These include some anti-psychotic medications, cardiac medications such as dofetilide, used for arrhythmia, and pain medications such as Vicodin or methadone.

Women who take the inhibitor Aromasin should also avoid certain antibiotics, antidepressants such as St. John’s Wort, anticonvulsants, and grapefruit and Seville oranges.

Tamoxifen, which has been used for some 25 years, binds to receptors on breast cancer cells and blocks estrogen-positive cancer cells. It is the most widely prescribed medication for breast cancer, Farley said.

Certain antidepressants, anti-psychotic drugs, cardiac medications such as some blood thinners and those used for arrhythmia, anti-fungals such as Lamisil, and estradiol should be avoided by those on tamoxifen. Other medications, such as the calcium reducer Sensipar and Vaprisol, used to reduce sodium levels, should also be avoided, he said.

There are drugs that can be used with tamoxifen to alleviate certain conditions and these should be discussed and monitored by a patient’s oncologist.

While most people don’t think twice about taking vitamins, they, too, can cause complications. For patients taking the breast cancer medication Xeloda, for example, he looks for B vitamins and folic acid. “We think of B vitamins as relatively benign, but they actually make Xeloda work too well,” he said, subjecting patients to “super side effects.”

For women on either tamoxifen or an aromatase inhibitor, some products commonly found in food can be dangerous if taken in concentrated forms, such as ginseng, star anise, alfalfa, anise, fennel, saw palmetto, black/blue cohosh, flaxseed, licorice, red raspberry leaf, and valerian.

For patients undergoing surgery, some substances may impact bleeding: garlic, ginger, gingko, glucosamine, green tea, and guarana, as well as high does of Vitamin E and fish oil.

The role of the liver


All drugs go through the liver to be activated or inactivated. To do this they need an enzyme, Farley explained. “There are a lot of medications that compete for the same enzymes and that’s where a lot of your drug interactions take place.”

When a drug competes with tamoxifen, for example, for the same enzyme, the tamoxifen could not be activated and thus be rendered ineffective. Certain antidepressants and anti-anxiety medications are the biggest to watch out for when on tamoxifen.

One of the most important enzymes is known as CYP3A4, which Farley said is also the “grapefruit” enzyme because it is the one grapefruit will inhibit from activating certain drugs.

“Whenever it comes to grapefruit I say make sure your medication doesn’t go through that enzyme,” he said, “because a majority of meds do.”

The pharmacist

“I think it’s important whenever you approach a supplement, even if it’s herbal or even if it’s a multi-vitamin, that you just read the contents of it. … Take a look at the percentages and have it evaluated by a pharmacist,” he said.

He characterized pharmacists as “the most accessible healthcare providers.” They can tell if a product has phyto-estrogens or will interact with someone’s therapy in any other way.

Anyone interested in speaking with Farley may call 203-852-3284.

The Post Treatment Breast Cancer Survivors Support Group meets monthly at Wilton Library. It is led by Nina Marino, LCSW, who was the clinical director for 15 years of the former Breast Cancer Survival Center and is a breast cancer survivor. If anyone has questions about the group they may call or email her at  203-644-2921 or cancersurvival2@aol.com. The next meeting is Jan. 8.