The way tamoxifen works is you’re depriving your cancer cells of estrogen, which is their nutrition, so that will only work for the cancers that are estrogen-fed or progesterone-fed. Nikita Shah More Quotes by Nikita Shah More Quotes From Nikita Shah Patients willsay I started taking tamoxifen and I gained 40 pounds, but that’s probably a combination of hormonal and lifestyle changes they’re going through. Tamoxifen can cause some fluid retention, and it could maybe cause a 2- or 3-pound weight gain, but beyond that there are probably other things going on as well. Nikita Shah health If a woman becomes post-menopausal during those five or 10 years she’s on tamoxifen, we will switch her to this other group of drugs that is 20 to 25 percent more effective. Nikita Shah health