Hi Sarah, 

I noticed you haven't had a reply yet so I just wanted to welcome you to the Cancer Chat community and let you know how pleased I am about the good news you and your mum both received.

As you'll see here, diarrhoea and constipation are possible side effects of Tamoxifen but if the problems you're contending with are becoming unmanageable or difficult to live with then do be sure to let your doctor know.

Hopefully some of our members who have been in a similar position will share their experiences with you soon but if you'd like to discuss this with our team of cancer nurses, they're available on 0808 800 4040, Monday - Friday between 9a.m - 5p.m.

Kind regards,

Steph, Cancer Chat Moderator

Hi Sasha,

I live in the US and was on endocrine therapy for 5 years, the last 2 being tamoxifen. It gave me terrible gastric problems. IBS, reflux, burning mouth. I have been off it now for 6 months but am still struggling with the burning mouth every time I eat. The IBS hasn't gotten any better either. I would like to tell you that there is light at the end of the tunnel but so far I'm not seeing it. Anyway, just wanted to reach out to let you know that "YES" tamoxifen causes digestive issues! 

Hi Sarah, I can only imagine how difficult that must have been for both you and your mum to be diagnosed within a short time frame. I can wholly empathise on the timing in conjunction with covid as I was diagnosed with breast cancer in August 2020. I've been taking Tamoxifen since November 2020 and have suffered all sorts of side effects. I've determined that brand does make a difference, but the best brand for me in terms of my internal thermostat and being able to get some sleep gives me a hairy chin, piles the weight on and I'm definitely struggling with loose bowel movements all too often. I recently had the FIT poo test and it came back negative for bowel cancer so that's reassuring. The doctor didn't suggest my tummy troubles were tamoxifen related but that I may have IBS... I think that tamoxifen is surely a contributing factor though!

I have had constant sub pubic pain for 19yrs. I was diagnosed with Interstitial Cystitus but later told this was wrong. I then was diagnosed with breast cancer and had a mastectomy. At the time of diagnosis I noticed the pain changed. It took 6months to get a barium meal xray and I was told I had rectocele and diverticular disease. I began taking tamoxifen after radiotherapy. The pain developed and ended up in A&E but sent home. CT Scan showed nothing and had changed. 5 months further on I began bleeding from my bladder (having had this checked out with a scope previously I was not referred back); I also began bleeding from my rectum (I have had piles for years but the pain was debilitating now and using supositories to cope). Aftre 4th Fit Test because of problems with labelling I finally got a positive for blood in poo. So after 9 months on tamoxifen and 3 months on metformin I chose to stop on Jan 1st. After 3 lots of antibiotics; I am now in March and pain has subsided. To also help with pain I told Dr to prescribe amatryptaline; which has enabled me to sleep at noght and some effect on pain. So now I am afraid to return to Tamoxifen and Metformin as the rectal pain and right quadrant pain was so bad. I personally believe that I had an infection as there was a smell and this was also picked up by my friends dog. I feel abandoned by the medical profession when I have been in terrible pain. I was told that I was trumatised by the mastectomy. This is gas lighting women to shut them up! I have been traumatised by the degree and longevity of pain that effectively I have had to tell GPs what tests to do and what to offer me. I have had 4 trips to A&E once sent by another GP who saw the photos of the blood; I came away after 7 hours and being told I was having a period; I went through menopause 20 years ago.