Singulair and 2pm

My 10 year old son has asthma. His inhaler is not working so the Dr. put him on Singular yesterday. I had him take one right when we got it. I then dropped him off at a friends house. Around 2pm I picked him up. He fell right asleep when we got home. He woke up crying. He proceded to cry & be totally unreasonable for 5 hours (until bedtime). He told us he didn't want to play football & he didn't like it (this from a kid who lives for football). He then proceded to call his coach & quit football. We tried to console him but there was no consoling him. This was all after being on it for less than 12 hours. I think the only reason we noticed this dramatic change in demeanor was because his is normally a very good kid & he instantly became uncontrollable. I then called his friends mom & according to his friends older sister he was 'out of it' for most of the time he was there & kept asking the same questions over & over. Needless to say he will not be taking another Singular pill! I have notified my son's Dr. of this & hopefully they will report it to the company.