Cysteinyl leukotrienes (CysLT) are important, biologically active bio-molecules, which extensive role in physiologic and pathologic processes becomes clearer and better understood. They are synthesized in the multistage 5-lipooxygenase pathway, which can occur in many different cells and owing to intermediate exchange is not limited to those which include complete set of enzymes – “transcellular biosynthesis”. CysLTs act as mediators and modulators of inflammatory reactions and their receptors are omnipresent in human body.

Their particular significance in allergic disorders, especially in allergic asthma, is reflected by their influence at many stages of disease development, beginning with hematopoiesis regulation, inflammatory cells survival increase, through chemotaxis, regulation of histamine receptor expression, neural muscle control modulation and finally vasodilatation and remodeling. Urine and sputum concentration of leukotrienes correlate with disease control and severity.

Complexity of CysLTs synthesis, renders therapeutic intervention theoretically possible and feasible at many stages, but currently only two modalities are available – inhibition of 5-lipooxygenase activity and blockade of CysLT receptors. Number of clinical trials proved leukotriene antagonists safe and efficient in allergic asthma, which was acknowledged by inclusion of those pharmaceutics in GINA guidelines. Antileukotrienes are used especially in therapy of patients suffering from aspirin-induced asthma, exercise-induced asthma, in coexistence of asthma and allergic rhinitis and in patients unable to control the disease with primary therapeutics.