Tamoxifen and IBS?

EddyS

I've been on Tamoxifen for 7 months. I get the occasional hot flash (not so bad), but my IBS (irritable bowel syndrome) is through the roof! I get gas, bloating, and stomach cramps all the time. I know that Tamoxifen increases the estrogen in your gut, and estrogen slows the gut down, so this does not surprise me given that I already had IBS. I'm not constipated, though I have to be careful in that regard. But the roiling gut (noisy!) and burping and cramping etc. is just ridiculous. I can't digest any animal or dairy fat at all ever, and quit frankly half the time it seems like I can only eat yogurt and chicken soup. I certainly have not gained weight on this drug! The terrible IBS is the only bad side effect I am having. Everything else if fine.  Is anyone else having trouble with their gut since starting Tamoxifen?

Anonymous

Never heard of that SE with tamoxifen. I had IBS years ago, but haven't had a problem in many years. Took tamox for 5 years without any digestive problems. sorry to hear  you're  having issues with it.

anne

EddyS

VERY interesting update on my original post six years ago!

I could find nothing back in 2010 about the Tamoxifen/IBS connection on the web or from the nurses or doctors at the Dana Farber here in Boston, which is considered one of the finest cancer hospitals in the world. Go figure. Looking on the web now, I still find very little! Here is my experience and what I learned from it.

I have always suffered from IBS, but three months on Tamoxifen pushed it through the roof! What had been a chronic, manageable issue had become acute. I hit the web and found a promising description of Bacterial Overgrowth of the small gut. Stopped eating carbs -- my pain stopped by the end of first day.

After more research I discovered that Tamoxifen floods your gut with estrogen, just like when you are pregnant. Estrogen in your gut slows your digestion down so you can absorb more nutrician for your baby. And since normally your small gut is ALWAYS moving to push the bacteria in your food through quickly, making your small gut too slow can lead to the bad bacteria multiplying. Most of those bad bacteria eat carbs and create huge gas which leads to terrible IBS. So cutting off their carb supply means no more gas and pain.

I stopped the tamoxifen (I'd had stage 1, grade 1 lobular -- clean margin lumpectomy, nothing in nodes, low risk). After a a diagnosis of bacterial overgrow and a year of no carbs ( I lost too much weight believe it or not) I was working my way though useless antibiotics because the big gun I needed (Xifaxan 550mg) was $3,000 for a full dosage and BC/BS wouldn't cover it until I'd tried the cheaper antibiotics. Then I got a bag stomach flu which triggered a volvulus (full twisting of the gut) which is about 1,000x more painful than childbirth plus life threatening. Rushed to hospital in ambulance, gut untwisted on its own suddenly, many hours later, I was allowed to go home and meet a surgeon the next day. Had the surgery to correct a previously undiagnosed birth defect and finally got the Xifaxan to fix my bacterial overgrowth.

Turns out one of the main underlying cause of my chronic IBS was a partially mal rotated small bowel. This is a very common, undiagnosed birth defect. The much improved imaging we now have is making the diagnosis more common. A fully mal rotated small bowel is the birth defect that causes newborns to be rushed into surgery after projectile vomiting their first meal. My partially mal rotated small bowel created a narrowing in my gut which slowed my digestion down and lead to gas and cramping. The tamoxifen slowed it down even further, leading to the bacterial overgrowth and the volvulus.

And now my IBS is practically gone! I still have a cranky gut, which does cramp and spasm on occasion, but basically it's better than it has ever been and what issues I do have are totally manageable.

So Tamoxifen can easily trigger serious IBS in women taking this drug. Doctors and nurses take notice!! Anyone suffering can stop carbs for a day to see if carb sensitive bacterial overgrowth might be the culprit. FYI, even after a year of no carbs and an operation to fix the narrowing in my gut, I STILL needed the Xifaxan to kill the bacterial overgrowth. It wasn't until after a full course of Xifaxen that I was finally able to eat carbs again without pain. Doctors, nurses AND BC/BS of MA take notice!

To any woman struggling with IBS while on Tamoxifen, keep trying to get the help you need!The only thing more complicated than your gut is your brain, so don't get discouraged if the problem is multilayered. Good luck!!

jojo9999

thanks for posting your story. very interesting. so many reasons to cut out carbs!

bookgal

Wow! Thank you for the update! Would you mind sharing what tests you had that helped with your diagnosis?. Was your white count high and that led to the bacterial infection diagnosis or did you have other GI tests?

I have been in and out of the ER in the past years with sudden and severe abdominal pain, esp upper gi small bowel inflammation. It lasts for days and takes a month before I can eat a semi normal diet ! I eat a lot of carbs because they are easier to digest which is what has been recommended by drs.The only answers I have had from Drs are maybe its viral/ food poisoning. It is to the point that I will not eat out any more.

Never thought of a tamoxifen connection. I have long history with IBS so figured that my post chemo low white count was to blame for my inability to fight off food borne illnesses. Had no idea that tamoxifen could slow the peristalsis of the GI tract and contribute to GI problems!

I am really glad I popped back into this forum

Thank you for sharing!