montelukast + cetirizine

Montelukast + cetirizine is a fixed-dose combination of two oral small molecule drugs used primarily for the treatment and prevention of allergic conditions such as seasonal allergic rhinitis and, in some cases, thyroid eye disease. Montelukast is a leukotriene receptor antagonist that blocks cysteinyl leukotriene receptors, reducing inflammation and bronchoconstriction. Cetirizine is a second-generation antihistamine that selectively antagonizes histamine H1 receptors, thereby reducing symptoms like sneezing, itching, rhinorrhea, and congestion. The combination has been shown to be more effective than cetirizine alone in preventing certain allergy symptoms (such as eye itching and nasal symptoms) when started prophylactically before allergen exposure[1][3]. It may also have utility in managing mild to moderate orbital congestion in thyroid eye disease[4].