@gwinter- Good morning everyone. I wrote several weeks ago to say that I've been on Arimidex for 15 months now and the side effects for me, anyway, are hard to tolerate. Bone and joint pain, weakness in my knees, a general feeling that I've aged about 100 years. (I'm 74 now!) I just wrote a pretty lengthy email to my Oncologist enumerating all these symptoms and more, and asking for her experience and feedback about other choices of AI's. she said other people have fewer side effects from Letrozole and/or Tomoxifen (not an AI)). I know that Arimidex is said to be the most effective in preventing a recurrence, so I am conflicted! I'd love to hear feedback from anyone who has switched from Arimidex to another AI to see if you found relief from side effects.