Leukotriene receptor antagonist used for bronchial asthma is :
**Core Concept**
Leukotriene receptor antagonists are a class of medications used to manage asthma by blocking the action of leukotrienes, which are pro-inflammatory mediators involved in the pathogenesis of asthma. These medications are particularly useful for patients who require long-term control of asthma symptoms.
**Why the Correct Answer is Right**
Montelukast is a selective cysteinyl leukotriene receptor 1 (CysLT1) antagonist that inhibits the action of leukotrienes on their receptors in the airways, resulting in reduced inflammation, bronchoconstriction, and mucus production. This mechanism of action is beneficial for patients with asthma, as it helps to control symptoms and prevent exacerbations.
**Why Each Wrong Option is Incorrect**
**Option A:** Zafirlukast is another leukotriene receptor antagonist, but it is not the best answer choice in this case.
**Option B:** Ciclesonide is an inhaled corticosteroid, not a leukotriene receptor antagonist.
**Option C:** Fexofenadine is an antihistamine, used to treat allergic rhinitis and urticaria, but not asthma.
**Clinical Pearl / High-Yield Fact**
Montelukast is often used as add-on therapy to inhaled corticosteroids in patients with uncontrolled asthma.
**Correct Answer: C. Montelukast**