Our daughter is now 5 1/2 and has been taking singulair since she was two, when she was diagnosed with asthma. She also has a slew of food and environmental allergies. It was not until she started taking Advair that her asthma became controlled. Her allergies still seem to bother her occasionally. I feel since her asthma is under control why take two meds? I did not refill her Rx and we are on day two of no Singulair. She's had headaches for two days and feels lousy. After reading the side effects of this drug I may now have answers to the headaches she'd get often and the moodiness and the sleepless nights and the deep dark circles under her eyes and the diarrhea. We'll see what happens in the next few weeks, although I agree that dose of antihistamine now and then is much better than all this other nonsense!