My 11 year old step-daughter has been on Singulair for 3 years and has had trouble sleeping - waking up 8-10 times nightly, sometimes with terrible nightmares as listed on some of the other posts. Thank you so much for sharing this info. We took her to an ENT today and the only thing they offered was to take out her tonsils and adnoids but the were basically normal - all they wanted was money the way I see it. We are taking her off all her meds tonight; she also takes Asmanex, Nasonex and Allegra.