unrelenting laryngitis...it didn't go away until I stopped the drug. I have not taken it for around a month. I had multiple side effect taking the full adult dose. However, Singulair was very effective at halting my allergy symptoms. Allergy-wise it was one of the best summers since childhood. It also seemed to clear things up for the month after I quit. They say there is a fungal infection usually at the root of chroncity with sinusitis...well, maybe, just maybe Singulair cleared that up for me. I am, once again, experiening symptoms so, I have decided to give it a go once more. I am going to see if I can take it for a couple of days full strength and then go down to half or the pediatric dose. I was going to chuck it for good because I had headaches, laryngitis, muscle cramps, stomach and chest pains, extreme tiredness, dizziness and I became a very angry and unhappy depressed woman and that really is bad if you're already female and over fifty!! I'll post the effects of the new regimen I am going to try with the reduced dose and for a smaller length of time of use of the medication.