Paused tamoxifen, have questions
Hi!
I was diagnosed with invasive lobular breast cancer in October 2025 (42 years old). Lumpectomy and one lymph node removed in November 2025.
15 rounds of radiation through 3 weeks in jan-feb 2026(last radiation therapy feb 6).
Since Jan 3 2026 I have been on tamoxifen. It was honestly fine. I had some hot flashes followed by feeling very cold but figured out some things that worked for me (exercise, cold bedroom, own duvet and so on).
Just before easter I picked up some new tamoxifen at the pharmacy. I was asked if another manufacturer was ok (here they always recommend the manufacturer that is the cheapest at the moment, but you can choose to say no). I said yes, having noooo clue that it could affect any side effects.
Well. Little did I know I would become a zombie. Not myself AT ALL. Everything was numb and grey. Pretty much not functioning as a human. And also cramps. And difficulty exercising. It felt like I had no energy in my muscles. It felt like I was going to faint and I had to leave classes at my gym because I couldn't finish them. I couldn't exercise my dog properly and I was barely able to do my job (still on 50% sick leave). It was very horrible.
I met with my oncologist last week, who said that I couldn't live like that (I agreed). We agreed that I would pause tamoxifen for 4 weeks, just to make sure it was really side effects from tamoxifen and not just a depression. It's been a week since my last pill and it is like night and day. I feel like myself again. The gray mass that was covering me has lifted and I can feel every emotion again. It feels like I can here and see the world again I walk a minimum of 10 000 steps a day and can function at work. It is truly amazing!
But it also means there is only 3 weeks left until I get back on tamoxifen. I truly want to succeed in managing the medicine. Not to every cost, but I want to try everything my doctor suggests before giving up.
My doctor doesn't know about the switch of manufacturer - I didn't think about that when we met last week. But I'll tell him in June when we have our next meeting.
One of the main reasons I want to be able to take the medicine is that we have plans of trying for a baby in Jan 2028 (yes. I will be 45 😳 I will have to use donated eggs). I want to increase the chance for me to have a long and healthy life - I need that if I am going to have a baby late in life! This is also why I want to lose weight and then maintain a healthy weight.
The plan so far is:
Go back on tamoxifen and add a small dose of antidepressants. I am reluctant (but not totally against the idea)because I don't want to take something that will numb my feelings, or will make me gain weight/make it more difficult to lose weight. I've been on antidepressants before and some I liked and some weren't good for me at all.
If that doesn't work: take half the normal dose of tamoxifen. It is normally not recommended in my country because there is not enough research about it yet, but my doctor and I figure half the dose is better than no dose.
I am curious though if I should try to just go back on tamoxifen with no antidepressants, but switch back to my original manufacturer?
How would you have done?
Have you tried tamoxifen with antidepressants? How did it work for you?
How is your weight, have you been able to lose weight while on tamoxifen?
Did anyone else have a baby late in life after BC?
Long explanation and a lot of questions. Hoping to learn more about other peoples experiences 🩷