Leukotriene modifiers (LTMs) are medications designed to block a chemical mediator in our body (leukotrienes) that causes mucous production, swelling of the lining of the sinuses and lungs, spasm of the lungs, and recruitment of cells that contribute to allergic inflammation. Some LTMs work by blocking production of leukotrienes while others block the receptor for the inflammatory mediators. LTMs are approved to treat both nasal allergies and asthma. LTMs are available in the form of a pill or chewable tablet. There is, however, one LTM that also comes as granules that can be mixed in food for young children. Currently available LTMs are: - Montelukast (Singulair) - Zafirlukast (Accolate) - Zileuton (Zyflo)