Montelukast is a leukotriene receptor antagonist (LTRA) used for the maintenance treatment of asthma and to relieve symptoms of seasonal allergies.[1] It is usually administered orally. Montelukast blocks the action of leukotriene D4 on the cysteinyl leukotriene receptor CysLT1 in the lungs and bronchial tubes by binding to it. This reduces the bronchoconstriction otherwise caused by the leukotriene, and results in less inflammation. Because of its method of operation, it is not useful for the treatment of acute asthma attacks. Again because of its very specific focus of operation, it does not interact with other allergy medications such as theophylline.
Side effects
Side effects include gastrointestinal disturbances, hypersensitivity reactions, sleep disorders and increased bleeding tendency, aside from many other generic adverse reactions. Its use is associated with a higher incidence of Churg-Strauss syndrome (whether or not this drug is 'unmasking' subclinical Churg-Strauss is as yet uncertain). In March, 2008 the FDA announced that it would investigate whether mood changes and suicidal thoughts are possible side effects of drugs in this class, including the popular drug Singulair, which currently lists these side effects.[2]
Use with loratadine
Schering-Plough and Merck have sought permission to market a combined pill with loratadine (Claritin) and montelukast (Singulair), as many patients combine the two themselves. However, the FDA has found no benefit from a combined pill for seasonal allergies over taking the two drugs in combination[3], and on April 25, 2008, issued a "not approvable" letter for the combination.[4]
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