Hi, my nephew is 7 and has been on Letrozole for about 6 months now. He is now having inappropriate separation anxiety and great trouble with sleeping. My brother and sister-in-law are at a loss. I can’t find any information on letrozole except about its use for breast cancer. I am wondering if your child or anyone else that you know of has experienced any side effects with the letrozole? We are wondering if this new behavior is related to the letrozole. Any information you have would be appreciated. Thanks, Kris