Asthma is a chronic inflammatory illness with a temporary occlusion of airways. This narrowing is caused by a number of substances, e.g. leukotrienes, and particularly cysteineleukotrienes, that are a subject of arachidonic acid metabolism. It was discovered that leukotrienes are one of the main powerful factors responsible for airways narrowing. Therefore, the substances inhibiting arachidonic acid metabolism have been synthesised. These compounds include zafirlukast and zileuton. Their regular use improves the patency of airways, lowers the frequency of asthma attacks and reduces the use of other anti-asthmatic medication. Furthermore, zafirlukast and zileuton have few undesirable effects.

Keywords: Asthma, Leukotrienes, Arachidonic Acid, zafirlukast, zileuton