I am so so FURIOUS with Merck and Singulair! No child especially the innocence of a 4year should be ripped from them from the damn drug companies. Do you know Singulair is one of the biggest money makers for them. Not fair!! I wonder how they would like to pay for my sons mental health bills now!! at $175 a pop because I am not sending him to any old psychiatrist. His pediatrician said it can take up to 6months for Singulair to clear your system. However the Serotonin imbalance that it may create may not. You may need to be put on depression meds, as I am afraid my 4 year old, yes my 4 year old may be put on. And for those of you who wonder. He comes from a very happily married loving home, and no problems at his catholic school. He had no reason for his ugly symptoms of wanting to die at 4 years old. He has been medically evaluated for everything, including a CT and MRI and was cleared!!! It was the Singulair!!!!! Thank god we have all found this website. I wish you all luck and please inform as many as you can. I do not want to see anyone suffer anymore from this. Innocence has been lost. God be with the poor family who lost their 17year from suicide due to this med!!!