Ventalin symptoms and conditions

My 4 year old Son has had diarrhea from about the last 4 weeks... we have started some tests for Celiac disease but today it only occurred to me today that he has been on Singulair for about that time frame... after all the worry and reading these other storied Im even more convinced that it maybe the Singulair..
Im just hoping that someone might read this sometime today or the next couple of days to tell me if when they come off the singulair how long did it take for the diarrhea to pass. My son had is last tablet 2 nights ago ( so he has only been off it so far for one night. But he still has the diarrhea.. should it have started to come out of his system already.

Greetings - I have been taking Singulair for just over one week - since I have moved to a different town my asthma has been really bad - I have been visiting hospital once a week and using Flovent and Ventalin. I have not had a problem with asthma (except occassionally from exercise or cold air) for over 10 years. I am not or have not been on any drugs (not even aspirin) ecxept ventalin (only about a dozen puffs a year) for many many years. Since I have started the sungulair as well as symbicort inhaler I have been able to breath fine (first time in 4 months), however I have had extreme cramping in hands and feet and constant backache in lower back. My whole body is weak and sore and I am feeling fuzzy headed. It cannot be a coincidence, unless it is the symbicort, it must be the singulair!