In March 2008 the FDA informed healthcare professionals and patients in the US that it was investigating a possible association between the use of montelukast (Singulair) and behaviour/mood changes, suicidality and suicide.

The FDA requested manufacturers of products indicated for the treatment of asthma and/or allergic rhinitis that act through the leukotriene pathway (montelukast, zafirlukast, zileuton) to submit adverse event data for suicidality adverse events as well as mood and behavioural-related adverse events from all available placebo-controlled clinical trials.  Although the data submitted to the Agency to date do not suggest that any of these medicines are associated with suicide or suicidal behaviour, these clinical trials were not designed specifically to examine neuropsychiatric events. As a result, some events may not have been reported.

The FDA is continuing to review clinical trial data to assess other neuropsychiatric events related to drugs that act through the leukotriene pathway (montelukast, zafirlukast, zileuton). Due to the complexity of the analyses, the Agency anticipates that it may take up to 9 months to complete the ongoing evaluations.  As soon as this review is complete, FDA will communicate the conclusions and recommendations to the public.