My son is 12 years old and has been on Singulair for 6 years. He is constantly experiencing leg pains, headaches in the back of his head, stomach aches, nosebleeds, and a lot of forgetfulness. He is taking 5mg at bedtime. He is always not able to sleep, but once he finally falls asleep it is very hard to wake him in the mornings. I never would have thought that 1 pill a night would cause so much pain in my sons life. As of today He is OFF!!!!