Been on Singulair since 98. I am 53. I too get heart palpitations...

Been on Singulair since 98. I am 53. I too get heart palpitations and difficulty breathing for a short period a few minutes after taking it but only once in a while. It helps my asthma but if I go off of it for a while my breathing is quite impaired for 4 or 5 days then improves but not to the level achieved with the Singulair. I dream more and have some nasty nightmares especially if I take ibuprofin at bed time. The reason I go off of the drug periodically and take Ibuprofin is that I am much more succeptible to muscle cramping, spasms, hip pain and tendonitis while on this drug. I used to be a runner/racer but had to quit race training because my back and neck would cramp up. I get tendonitis easily in my forarms from activities that never bothered me before. I have had back spasms for 2 months that did not improve with ice, heat, Ibuprofin, chiropractic or physical therapy until I remembered the Singulair connection two days ago and stopped taking it. Today I am noticing improvement for the first time. Once my back heals up I think I will try reducing the dosage to 5 mg and see if it is enough to help my breathing without the muscle problems.