Singulair Side Effects: My son is almost 9, he has been on Singulair for 3 years. Last Fr http://www.medications.com/effect/view/30684 My son is almost 9, he has been on Singulair for 3 years. Last Friday the pulmonologist took him off of it. My son has been sleep walking since about the time he started singulair, have noticed major behavior changes. He gets very angry over nothing, he is I am glad to hear that you have an understanding doctor. So many Wed, 21 May 2008 22:24:55 -0400 http://www.medications.com/effect/view/30684?item=8512 I am glad to hear that you have an understanding doctor. So many of them just brush parents views aside, mine included. I still took my child off the medicine and have seen huge improvments. http://www.medications.com/effect/view/30684?item=8512