Montelukast

**Semantic type:** Pharmacologic Substance

**Definition:** A selective cysteinyl leukotriene receptor antagonist with anti-inflammatory and bronchodilating activities. Upon administration, montelukast selectively and competitively blocks the cysteinyl leukotriene 1 (CysLT1) receptor, preventing binding of the inflammatory mediator leukotriene D4 (LTD4). Inhibition of LTD4 activity results in inhibition of leukotriene-mediated inflammatory events including migration of eosinophils and neutrophils, adhesion of leukocytes to vascular endothelium, monocyte and neutrophil aggregation, increased airway edema, increased capillary permeability, and bronchoconstriction. The CysLT1 receptor is found in a number of tissues including spleen, lung, placenta, small intestine, and nasal mucosa, and in a variety of cell types including monocyte/macrophages, mast cells, eosinophils, CD34-positive hemopoietic progenitor cells, neutrophils and endothelial cells.

**Synonyms:** - MONTELUKAST - montelukast