My 4 year old dd has been taking Singulair for about a year. I stopped giving it to her during the winter months as she has seasonal allergies. But now that she is back on it I have noticed that she has frequent daytime urination, nightmares and muscle pains. We have had her checked for UTI's and diabetes and everything is fine. The dr. just says that her bowel is still growing. But when we stopped giving it to her in the winter she was fine. Now all of a sudden she is back to frequent daytime urination. I am going to discontinue and see what happens. I am really glad to find this sight!