Just a note to those of you who are using Singulair. I had the feeling as if I was getting the flu when I was on Singulair and later on, in smaller doses, I was aching all over my body. The doctor insisted that I try reducing the dose a little by little but in the end, I stopped using it of my own volition. I now wonder if it was the Vasculitis that was the causing and whether anything serious would be the outcome of it. Has anyone had any similar experiences with Singulair?