Things Interfering Tamoxifen’s Effectiveness
There are three things that can interfere with Tamoxifen. Is it possible that medications or food could interfere with Tamoxifen? Many women have wondered whether they're getting the most from their anti-estrogen therapy. After all, it's important to know that your therapy is working.
Doctors now understand that various foods and medications can interfere with Tamoxifen’s ability to help to prevent breast cancer recurrence.
Number one thing that can interfere with Tamoxifen is antidepressants. Some women are prescribed antidepressants to combat effects like hot flashes, anxiety and mood swings during menopause. While antidepressants can help to stabilize your mood, these drugs can also interfere with Tamoxifen’s effectiveness.
According to some studies, using certain antidepressants called SSRIs during taking Tamoxifen can more than double your chances for recurrence after two years. This is due to antidepressants’ ability to inhibit the liver enzyme CPY to V6, which is necessary to convert Tamoxifen into its active form. But don't stress. If you're postmenopausal and need antidepressants, then doctors may be able to switch you to an aromataste inhibitor, which is a different type of anti-estrogen therapy.
You may also be able to change to a non SSRI antidepressant, regardless of your age. Also, if you're approaching the five-year mark, then you should speak with your doctor about breast cancer index, a test that may help women with the er-positive early stage breast cancer decide with their doctors whether to extend or end anti- estrogen therapy after five years.
Similar to the antidepressants, grapefruit interferes with an important enzyme in your liver and intestine. Instead of inhibiting the effect of Tamoxifen, grapefruit can, actually, lead to excess estrogen in your body, inhibiting the metabolism of estrogen. This leads to a buildup of the hormone, fueling your cancer. If you find yourself missing the grapefruit in your diet, try substituting other fruit that play nice with your body.
Once again, it all comes back to the enzymes in your liver and intestine, similar to the negative side effects of SSRIs and women taking Tamoxifen. Benadryl is also called Diphenhydramine. It can inhibit the enzyme CPY2D6, which is necessary to convert Tamoxifen into its active form. Some allergies or sleep medications may also contain Diphenhydramine. If you're taking Benadryl for allergies or as a sleep aid, then be sure to ask your doctor about alternative medications.
In fact, be sure to ask your doctor any questions you have about what can be interfering with your therapy. Many women struggle with the side effects of Tamoxifen. That's why it's important to limit anything that can be compromising your anti-estrogen therapy.