I have been taking Anastrozole for 3 full months. I too had stage 1a invasive ductal carcinoma with no lymph nodes/lumpectomy,radiation and finishing my year of targeted therapy in July. I have severe arthritis in my knees for years and pain in my right groin and hip for about a year . I think my groin pain when walking has been exasperated by my cancer treatment but not sure if the arthritis has just worsened because of age . I am a healthy 80 year old. So far I haven’t experienced any significant side effects from the Anastrozole that I am aware of , however I am aware side effects can appear anytime. I plan on asking my oncologist her thoughts on Claritin to help with this joint pain if it is related to my targeted treatment of herceptin and the possibility the Anastrozole will also contribute to my pain . Any thoughts ?