Singulair is the trade name for the prescription medication Montelukast. This medication is classified as a leukotriene receptor antagonist. Singulair is most commonly used in the treatment of asthma as well as to relieve symptoms associated with seasonal allergies. Singulair is effective in the treatment of these conditions because it blocks the action of leukotriene D4 and reduces the bronchoconstriction that would be caused by leukotriene, causing much less inflammation of the lungs and sinuses.

While Singulair is very effective in treating asthma and allergies, it is not indicated for the treatment of acute asthma. Currently Singulair is only offered as a brand name, though the patent will expire in August of 2012 and shortly thereafter it should become available as a generic, making it much more accessible prescription medication for the majority of the population. A generic for Singulair may not be available until some time in 2013, assuming the patent is not extended or renewed.

Like all medications currently on the market, Singulair may be associated with some unintended side effects that occur simultaneously with the intended results. These side effects may include sleep disorders, gastrointestinal upset, and increased bleeding at the site of an abrasion. Singulair is also associated with an increased risk of Churg-Strauss syndrome. Additionally, this medication has been associated with mood changes including but not limited to suicidal ideation. Others will experience agitation, aggression, anxiousness, sleep disturbances, depression, irritability, tremor, and restlessness.