Hello Priyanka Thanks for your query. How is your son now ? Regarding your question , Montair contains the drug Montelukast,which is a Leukotriene [cys LT1] receptor antagonist.It blocks the action of leukotriene and prevents leukotriene mediated inflammation and bronchoconstriction.It is used in prophylactic therapy of mild to moderate asthma,in allergic rhinitis ,urticaria etc.Montelukast is usually safe drug.SideEffects are GI disturbances,headache & rashes.Few cases of Churg-Strauss syndrome have been reported. In a report FDA mentioned about the possibility of neuropsychiatric side effects with leukotriene modulator drugs like Montelukast. Although clinical trials only revealed an increased risk of insomnia, post-marketing surveillance showed that the drugs are associated with a possible increase in suicidal behavior and other side effects such as agitation, aggression, anxiousness, dream abnormalities and hallucinations, depression, irritability, restlessness, and tremor. Update here how your son stays ... Take care.