Singulair Side Effects: My 13 year old son started taking singulair Nov 13, 2008 for seas http://www.medications.com/effect/view/39436 My 13 year old son started taking singulair Nov 13, 2008 for seasonal allergies. Three weeks later teachers at school recognized a change in behavior that was not typical or noticed prior to the medication. The end of Dec. 2008 loss of appetite and increase you are not alone,visit www.parentsforsafety.org for more info.IF Sat, 28 Feb 2009 08:53:24 -0500 http://www.medications.com/effect/view/39436?item=17559 you are not alone,visit www.parentsforsafety.org for more info.IF YOU CAN ASK YOUR DOC TO CHECK ENSOPHILLA levels in the blood. we have a theory. Good Good luck http://www.medications.com/effect/view/39436?item=17559 These are other side effect my 13 year old has had to deal with i Sat, 28 Feb 2009 16:34:56 -0500 http://www.medications.com/effect/view/39436?item=17565 These are other side effect my 13 year old has had to deal with in the last month and a half, due to singulair in my opinion. Mood changes, bad nightmares & vivid dreams, thoughts of hurting others to the point of wishing they were dead, anxieties & panic http://www.medications.com/effect/view/39436?item=17565