How does montelukast work?
Montelukast is one of a group of new drugs which work by blocking the effect of an important group of substances released in the lungs during the process which leads to asthma. These substances are called leukotrienes. Just as antihistamines stop a substance called histamine from working, so montelukast stops leukotrienes from working. Leukotrienes are important in asthma because their release from cells in the lungs causes narrowing of the air passages, for example by making the muscles around the air tubes contract. So one benefit of montelukast is that it acts against this muscle contraction, and so against narrowing of the air passages. But leukotrienes act in quite a number of ways to help produce asthma. We now know that in asthma the air tubes are not just narrowed by contracting muscle fibres, but that the lining membrane of the air tubes is inflamed, looking red in colour. The microscope shows that the inflamed lining membrane is also full of cells we normally think of as whit
