Has anyone in the U.S. been prescribed 5mg of Tamoxifen

I've read that it should not be broken in half . It should be taken as a whole and every other day (10 mg )

If it a solid tablet what would be the reasoning?

Hi! I am on tamoxifen 5 mg. I cut my 10mg in half. My oncologist told me the 5mg everyday was fine because I could not tolerate the 20 what so ever. Bad pelvic cramps and bladder pains. The 10 was ok but I still had bladder issues daily. I am pre menopausal and I never really had an issue so far with hot flashes or night sweats. I do get them occasionally but I got them before starting tamoxifen so I really do not think they increased with tamoxifen. As far as hair loss. Yes! I thought I was crazy. But even at the 10mg everyday I was still experiencing it. It just recently stopped and I am so happy! I have long fine hair but a lot of it. So I never felt I saw bald spots or anything . But right after I washed it I could tell. Even on days I did not wash it, I could tell. I style my hair for work everyday and it was noticeable the amount I saw in the comb. I was starting to get really really upset . But it has changed! I have always been a heavy shedder I should note. But this was even a little too much for me. Also my hair felt drier on tamoxifen 10mg. But I did go back to my old shampoo so this could be a factor too. Hope this helps.

I use a pill cutter. I work in a pharmacy. Tamoxifen is not an extended release drug so yes you can cut it half. It does not have a score, So you must try to be precise when you cut it. That’s why a pill cutter is best.

I was prescribed Tamoxifen 20mg--my cancer is Es+Pr-HR2-. Perhaps the type of cancer makes a difference in amount needed.

christylv , Thank you for your input . I have long time to go with Tamoxifen .... Hope it's not going to be worse . Wishing you best of health for rest of your life ! ❤️🙏🏻

Your statement concurs with my understanding of dosing for Tamoxifen. My cancer is also IDC - ER/PR positive Her2-. 20mg is desired and what has been studied.

It is my understanding that 5mg is seen as preventative or used with DCIS stage 0.
I also believe that the study referenced for 5mg only looks at 3 years.
My oncologist was a hard - “no”.
All of that said, for me 10mg is tolerable and 20 is not.

I was prescribed 20 mgs of Tamoxifin to start taking the day after I finished radiation on 2/18/25. I had a lumpectomy, small 0.9 cm but had 3 different cancers. DCIS, Lobular In Situ and IDC-estrogen/progesterone--pretty unheard of to have 3. Had tumor removed, did 21 radiation treatments. Did fine, I thought. So, three days later after taking the Tamoxifin was at the emergency room as I was so constipated. ER did nothing, sent me home with suppositories. Four days later I was bleeding, ended up with hemorroids and a deep fisher, That was 2/22/25. It is now 4/29/2025 still dealing with the fissure and now scheduled for surgery 5/9 - hopefully to fix fissure. My system just could not handle. My cancer doctor wants me to start it again, even if lower dose, but I am to scared to try. It has been a long painful experience, I do have a pre-existing issue as I take Linzess, guessing that was the problem. They don't know and any other medications have more side effects.

So I guess I will be taking my chances of the cancer coming back, but hopefully will get this fixed and at least I will have a life again for whatever time. I am pretty healthy otherwise. I am 74 so anytime left will enjoy!

I am truly sorry this happened to you. Could you get a second opinion? Did they recommend taking Magnesium Glycinate with the meds? It can help with constipation. There are many articles on women over 70 with small tumors not needing further treatment after surgery. You can Google the article, one is by Harvard. With IDC, IDS, and Lobular in Situ is not uncommon in older women.

I was 51 and took Tamoxifen for 5 years. I did get BC again 25 years later but it was not a reoccurrence from the first. I have never heard of. Your problem with Tamoxifen, but everyone is different. However, for the 5 years I took it I literally burned like hot flashes 24/7. I had a fan with me at all times.. it did leave me with severe fibromyalgia. I guess I should have known something wasn’t right burning like that, but at that time I refused chemo and felt I had to stay with it. There should be other options now if that’s what you decide. A very personal choice. Best wishes