Is this Arimidex? If so, it is an aromatase inhibitor usually prescribed for post menopausal women (the other is Femara). I have only used it briefly as I have been on Femara for over 4 years (will be on for 5 in all) and appear to have had no side effects other than the known effect of a reduction in bone density. Perhaps some others who have been on Arimidex can comment?