Montelukast (trade names Singulair, Montelo-10 and Monteflo in India) is a leukotriene receptor antagonist (LTRA) used for the maintenance treatment of asthma and to relieve symptoms of seasonal allergies. It is usually administered orally. Montelukast is a CysLT1 antagonist; it blocks the action of leukotriene D4 (and secondary ligands LTC4 and LTE4) 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 asthma medications such as theophylline. Another leukotriene receptor antagonist is zafirlukast (Accolate), taken twice daily.
Contributions by CheMoBot, Fvasconcellos, and M1ss1ontomars2k4.