After reading this website and struggling with some pretty severe side effects with our son over the last 5 years, we decided to replace Singulair with a different asthma med. Guess what? After 2 weeks, we saw a TOTAL turnaround with our son! It was like night and day. I can't believe we let our son struggle with this side effect for 5 years. Singulair DID work great for our boy, but it just isn't worth the side effect that he had.