Which of the following is NOT classified as a leukotriene receptor antagonist?

Fluticasone is the correct answer as it is not classified as a leukotriene receptor antagonist. Instead, it is a corticosteroid that helps reduce inflammation in the airways, thereby controlling asthma symptoms by acting at a different mechanism compared to leukotriene receptor antagonists.

Leukotriene receptor antagonists like zafirlukast, montelukast, and zileuton specifically target leukotrienes, which are inflammatory mediators that can contribute to bronchoconstriction and airway inflammation in asthma. These medications work by blocking the action of leukotrienes on their receptors, leading to decreased inflammation and improved airflow. In contrast, fluticasone acts primarily by suppressing the immune response and reducing overall airway inflammation rather than directly interacting with leukotriene receptors. This distinction is key in understanding the various classes of asthma medications and their specific roles in treatment.