My 12 year old son given Singulair yesterday by our pediatrician ...

My 12 year old son given Singulair yesterday by our pediatrician for a mild allergy problem (a sample package with a prescription to fill). There were no issueswith the first dose but he began vomiting after breakfast and again later that morning. After reading these posts I realize that as a parent we must be more cautious of the medications we give to our children and investigate possible side effects prior to treatment, no matter what the doctors say. I have not read any other signs of vomiting from these posts but a lot of other possible side effects that I am just not willing to take any chances with this medication. In the trash it goes.