My 81 year old Mother has breast cancer. They had to do a complete mastectomy. Chemo was only option and she did not want to do it. That leads up to my question. She is a serious diabetic already, her Oncologist wanted her to try to take Femara (Letrozole), she has been taking it for 3 full weeks and her sugar is dropping like crazy! Causing Diabetect Comas. Is this medicine causing this to happen?