I have been on arimidex for about 2 months (since Feb. 2009), switched from tamoxifen after 1 year on tamoxifen. My white blood cell count the month before I started arimidex (Jan.) was 4.2. When I had a blood test more than 2 weeks ago (April 8), my WBC count was 3.3. Could this be a side effect of arimidex?
FYI -- I was diagnosed in May 2007: IDC, stage 1, 1cm., e.r. +, grade 3, negative lymph nodes. I had chemo (1 infusion TC, 6 infusions CMF) Aug. 2007 to Jan. 2008, radiation for 7 weeks from Feb. to mid March 2008. I had a severe reaction to Neulasta, so I had to stop taking it and my WBC count was a major issue throughout the chemo. After chemo my WBC count was slow to come back up, and it was determined that under the best of circumstances my WBC count is low normal. The highest it has been post-chemo and post-rads was 4.8, at the end of 2008.