cause of muscular skeleton pain with arimidex

after a lumpectomy I was placed first on Tamoxafin and then on Arimidex.  both drugs caused mental confusion and profound depression as well as pain in my back.  It is not joint pain, it feels more as if I have severe muscle spasms in my buttocks.  when they occur it is impossible for me to move until the spasm passes.  Can you tell me what would have caused this and what I can do about it.  I take ibuprofin and the relief lasts about 4 hours. I'd prefer not having to take any pain killers.  Does anyone relate to this?

[CCF-RN,MSN-rf]

Dear epp:  Back pain has been reported in people taking Arimidex.  However, it would be important to be certain that there was no other problem in your back to which the pain could be attributed.  If there is reasonable certainty on the part of your oncologist that the pain is due to the Arimidex, the options may include continuing with some type of pain reliever or switching or stopping the drug.  You should discuss these options with your oncologist along with the risks and benefits to you.  This may help you in making a decision moving forward.

[Epp]

I've done as you've suggested, my question regards what causes the pain?  What is it that the drug does that results in pain in some people?

thanks

[Glass Slipper]

I was on Femara for 14 months.  I experienced excruciating joint and back pain.  I had an MRI to rule out any other possible reasons for my pain.  My MRI was negative.  I switched to Arimidex one month ago.  I am experiencing thesame musclular skeletal pain and joint and back pain.  It is especially bad at night and first thing in the morning.  It gets better as the day progresses.  Advil helps.  Please let me know if anyone else is having similar problems with these drugs.