I was on 10 mg. Tamoxifen for 18 months. It was all I could take without having spotting. I had what I would call PMS symptoms daily. I even went slightly crazy out in public a few times. I hung on on as long as I could. I would suggest you go down to 10 mg. and see if you can tolerate that. My oncologist said it was better than doing nothing. Everyone reacts to it so differently; I would never tell anyone not to try it, even if they can only do half a dose. My oncologist wanted to put me on SSRIS to counteract the Tamoxifen side effects. I guess it is a common practice. I said no. We should all be given Breast Cancer Index tests to see how badly we need to be on these kinds of medications. If I had the money, I would pay out of pocket for one, tomorrow.