I started Anastrozole, generic form of Arimidex, last October following radiation. The first side effect I noticed was brain fog and some memory loss. When I checked on-line for side effects of Anastrozole, brain fog and mild memory problems were side effects listed. I also started to have some depression and anxiety around Thanksgiving. I kept taking the Anastrozole through the first part of the year, but in February I started breaking out in hives. Hives are another rare side effect. I treated the hives with over the counter medication, but couldn’t stand the itching and called my oncologist. She switched me to tamoxifen. The hives didn’t get much better on the tamoxifen. In late February, I couldn’t stand the itching any longer and went to an InstaCare office. The doctor there said it’s possible that my cancer meds. we’re the cause and prescribed a week course of prednisone. That cleared up the itching and I haven’t had hives for a little over a month. I did start my tomoxifin again when I finished the cortisone. I’m not sure the hives were from either the Anastrozole, or the tamoxifen, but it’s possible and since I wasn’t doing anything out of the ordinary, I suspect the cancer meds were the culprit. I did make an appointment with an allergist and seeing her next week. I’m hoping she can determine the cause of the hives. I see my oncologist in a few weeks for a follow up visit and will talk to her about ALL of these issues, the brain fog/memory issues, depression, anxiety, and the dreadful hives! Having breast cancer is bad enough without having all these other issues from the medications that are supposed to help prevent a reccurance! Cancer sucks!!!!