Has anyone taking Tamoxifen experienced heartburn with abdominal pain?

I am a 74 yr old healthy before breast cancer (Stage 1B Invasive Lobular) 3 years ago. On AIs I had severe GI problems- abdominal pain, reflux, intractable diarrhea, nausea. I did 4 trials with 2 different AIs and I was so miserable and incapacitated with no quality of life. Given my age I decided to take my chances with the cancer recurring. After stopping the AIs it took several weeks before it cleared out of my system and the symptoms abated. I returned to good health and active life for a year, then my oncologist convinced me to try baby Tam-- 5 mg. I lasted a month and then got all the same reactions, even worse. It has been over 3 months since I went off the Tamoxifen and am still dealing with severe GI issues. I just consulted gastroenterologist who did a lot of testing that all came out negative, then did a colonoscopy even though I had one 3 years ago that showed no problems except mild asymptomatic diverticulosis (common at my age). Now he found my diverticulosis was much worse, and that I have what he called tortuous colon. This can be congenital but I never had it before and it can also be caused by prolonged constipation. I am sure that the AIs and the Tamoxifen are the cause. I am waiting to find out what recovery from this will entail and am very worried. At no point did my oncologist offer me any support for managing my GI side effect, just kept telling me that this was not a side effect that she had seen and was not usual. It may not be the most common side effect, but everyone is different and it was definitely a side effect for me. I started looking it up online and found that many women do have serious GI issues on these drugs., especially post-menopausal women. But estrogen blockers are all doctors have to reduce the chances of recurrence and they just look at the statistics. I do now live with the reality that my cancer may metastasize or recur in my remaining breast, but I feel that on the drugs life was not worth living. A younger woman might make a different calculus. I am doing all the alternative/ healthy active lifestyle and diet that I can and hope I can have a few more good years with my husband and to see my granddaughters grow up and finish my creative projects.

@antonina74 I am 72 & was diagnosed in August with ILC stage 1, no nodes. Did lumpectomy & 5-day radiation & am taking 10 mg Tamoxifen (started 1-1-26) to help with bone strength. For me, side effects are (yet another layer of) brain fog & a few pounds of weight gain which I'm battling to get rid of. Not terrible, but I wonder every day if I should even be taking the Tam! Many older women with early stage 1 breast cancer opt out of the hormone blockers & choose quality of life instead. Did you have any lymph node involvement? Did you do radiation? Overall, your healthy lifestyle choices will undoubtedly boost your chances of remaining cancer-free! Good for you! I'm sorry for your digestive issues. I haven't had those but yes, each of us reacts differently! It's a roller-coaster, this whole thing. Sending positive wishes to you for many healthy years ahead!

I understand But I feel one size doesn’t fit all If I hadn’t researched the possibility of try the drug by another manufacturer I don’t think I would have been staying on the prescribed dose 10 mg didn’t reduce some of the s/e’s for me but what a difference in trying another manufacturer I do have osteopenia which Oncologist felt would help with more bone loss. Hope it continues to reduce the s/e’s But I appreciate you clarifying response
Sally from CA

Consider investigating motility issues, SIBO, and sensitivities to gluten, histamines, and salicylates. And if you consume any alcohol, any at all, STOP. Gut bacteria is serious business and you need to get that right for nutrition, meds, and your immune system to work. GI testing yields useless data if not properly timed and sequenced. For example, two weeks after seeing me, a GI scheduled me for an upper colonoscopy to test for celiacs, plus a SIBO breath test, and two other tests. I researched them then cancelled all of it: the data would have been meaningless and my $ wasted because the procedures were not sequenced or timed at all. For example: you must ingest gluten for at least six weeks prior to the upper colonoscopy to stimulate a reaction that would surface the celiac’s. That GI was all about the coding + insurance $, not the outcomes: he would get his reimbursements while useless, inaccurate data would have left my issues unsolved. I changed GIs. Using the paid versions of ChatGPT and Gemini, I do my own research. It does not replace doctors, it makes me an informed, shrewd consumer of medical services, a consumer who asks better questions and better understands and manages my own health. I urge you to research anything in this post or your experience that is new to you. YOU are your best advocate, and the ONLY one totally vested in your best health outcomes.