## **Core Concept**
Exercise-induced asthma, also known as exercise-induced bronchospasm (EIB), is a condition where the airways constrict in response to physical exertion. This condition is prevalent among individuals with asthma but can also occur in people without a prior history of asthma. The underlying mechanism involves the release of inflammatory mediators and the contraction of bronchial smooth muscles in response to the drying and cooling of the airways during exercise.

## **Why the Correct Answer is Right**
The correct answer, **C. Salbutamol (Albuterol)**, is a short-acting β2 adrenergic receptor agonist (SABA) that is widely used for the relief of bronchospasm in conditions such as asthma and chronic obstructive pulmonary disease (COPD). Salbutamol works by stimulating β2 receptors in the lungs, leading to bronchodilation, which helps to prevent or alleviate the bronchospasm associated with exercise-induced asthma. Its quick onset of action makes it particularly useful for preventing EIB when taken before exercise.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Ipratropium bromide is an anticholinergic bronchodilator used in the maintenance and treatment of COPD and asthma. While it can help with bronchospasm, it is not the first choice for preventing exercise-induced asthma due to its slower onset of action compared to salbutamol.
- **Option B:** Montelukast is a leukotriene receptor antagonist used in the maintenance treatment of asthma and to relieve symptoms of seasonal allergies. It is not used for the acute prevention of exercise-induced bronchospasm.
- **Option D:** Beclomethasone is an inhaled corticosteroid used for long-term control of asthma symptoms and prevention of asthma symptoms. It is not used for immediate relief or prevention of exercise-induced asthma.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that for the prevention of exercise-induced bronchospasm, **salbutamol (albuterol)** should be taken 15-20 minutes before exercise. This timing allows the medication to take effect and provide protection during physical activity. Additionally, regular use of inhaled corticosteroids in asthmatic patients can also reduce the frequency and severity of EIB.

## **Correct Answer: C. Salbutamol.**