FDA is investigating a possible association between the use of Singulair and behavior/mood changes, suicidality (suicidal thinking and behavior) and suicide.  Singulair is a medicine in the drug class known as leukotriene receptor antagonists.  Singulair is used to treat asthma and the symptoms of allergic rhinitis (sneezing, stuffy nose, runny nose, itching of the nose) and to prevent exercise-induced asthma.

Over the past year, the maker of Singulair, Merck & Co, Inc., has updated the prescribing information and patient information for Singulair to include the following post-marketing adverse events: tremor (March 2007), depression (April 2007), suicidality (suicidal thinking and behavior) (October 2007), and anxiousness (February 2008).