Was on Arimdex for only 7 weeks and stopped due to side effects, in particular joint pain in hands. It has been about 10 weeks since I stopped and pain in hands is worse (I also have trigger thumbs & insomnia). Arimidex is suppose to have a half life in body of 8 days but it obviously can impact some people much worse than others-hot flushes have decreased significantly, just hoping that pain etc will gradually subside. My GP has ordered blood tests to check for any other causes but everything I have read about Arimidex points to it being he culprit.