Hi there, I have had the same problem. I was on Letrozole for a year then swapped to Tamoxifen last April. Within a couple of weeks of taking Tamoxifen I noticed that I needed to pee every couple of hours, sometimes more frequently. As a result I have increased the number of pelvic floor exercises I do each day and am training my bladder to go longer before the next pee.
I mentioned the bladder issue to my consultant in February. She agreed that it could be a side effect of Tamoxifen.
Has anybody else experienced an increase in frequency of peeing since they’ve started taking tamoxifen. No sign of infection but running to the loo all of the time. Not sure if a coincidence and may not be related, but would be interested in other peoples experience.