Montelukast is ?
**Core Concept**
Montelukast is a leukotriene receptor antagonist (LTRA) that plays a crucial role in the management of asthma and allergic rhinitis. It works by blocking the action of leukotrienes, which are pro-inflammatory mediators involved in the pathogenesis of these conditions.
**Why the Correct Answer is Right**
Montelukast specifically targets the cysteinyl leukotriene receptor 1 (CysLT1R), inhibiting the binding of cysteinyl leukotrienes (LTC4, LTD4, and LTE4) and thereby reducing inflammation, smooth muscle contraction, and mucus production in the airways. This action helps to alleviate symptoms of asthma and allergic rhinitis, such as wheezing, coughing, and nasal congestion.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because montelukast is not a bronchodilator, which is a class of medications that directly relax airway smooth muscle and improve lung function.
**Option B:** This option is incorrect because montelukast is not a corticosteroid, which is a class of medications that reduce inflammation and are commonly used in the treatment of asthma and allergic rhinitis.
**Option C:** This option is incorrect because montelukast is not an antihistamine, which is a class of medications that block the action of histamine and are used to treat allergic reactions.
**Clinical Pearl / High-Yield Fact**
Montelukast is often used as an add-on therapy to inhaled corticosteroids in patients with persistent asthma, and it is also effective in the treatment of seasonal allergic rhinitis.
**Correct Answer: C. Leukotriene receptor antagonist.**