ARIMIDEX can cause bone softening/weakening (osteoporosis) increasing the chance of fractures. In a clinical study in early
breast cancer, there were more fractures (including fractures of the spine, hip, and wrist) with ARIMIDEX (10%) than with tamoxifen (7%).
In a clinical study in early breast cancer, some patients taking ARIMIDEX had an increase in cholesterol. Skin reactions, allergic reactions, and changes in blood tests of liver function have also been reported.