Montelukast is a cysteinyl leukotriene 1 (CysLT₁) receptor antagonist (IC₅₀= 4.9 nM in HEK293 cell membranes expressing the human receptor).¹It is selective for CysLT₁over CysLT₂receptors (IC₅₀= >10,000 nM in COS-7 cell membranes expressing the human receptor).²Montelukast inhibits bronchoconstriction induced by leukotriene D₄in anesthetized guinea pigs (ED₅₀= 69 nmol/kg, p.o.).³It inhibits ovalbumin-induced airway hyperresponsiveness and increases in the number of total cells and eosinophils in bronchoalveolar lavage fluid (BALF) in a mouse model of allergic asthma when administered at doses of 3 and 10 mg/kg.⁴Formulations containing montelukast have been used in the treatment of asthma, allergic rhinitis, and exercise-induced bronchoconstriction.

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