I haven't done this specifically but have changed out meds for alternatives over side-effects before.
I was put on Letrozole (a similar inhibitor) and only felt the slightest of headaches and numbing sensations of all the terrifying things that can cause. Arimidex has a meaner list of side-effect possibilities compared to Tamoxifen but honestly, when one thing is hitting like a brick and there are alternatives out there I feel it's well worth trying. You can always just change back.
I hope it treats you gently. x