**Question:** DOC for acute attack of asthma in patients on Beta blockers

**Core Concept:** Beta blockers are medications that block beta-adrenergic receptors, commonly used to treat hypertension, angina, and heart failure. In asthma, beta-agonists are often used to relax bronchial smooth muscles and improve airflow, counteracting the bronchoconstrictive effects of the parasympathetic nervous system.

**Why the Correct Answer is Right:** For patients on beta-blockers who experience an acute asthma attack, a DOC (short for "short-acting" or "quick-acting") corticosteroid is recommended. This is because corticosteroids possess anti-inflammatory properties, which help to reduce airway inflammation and edema, thus improving airflow and alleviating symptoms.

**Why Each Wrong Option is Incorrect:**

A. Salbutamol (Albuterol): Salbutamol is a short-acting beta-agonist that would be contraindicated in patients on beta-blockers due to the potential for excessive bronchoconstriction and worsening of asthma symptoms.

B. Ipratropium: Ipratropium is a short-acting anticholinergic drug that works by blocking acetylcholine receptors. However, it is not a steroid and would not effectively address the underlying inflammation in the airways of an acute asthma attack.

C. Montelukast: Montelukast is a leukotriene modulator, which works by blocking leukotriene receptors. While leukotrienes contribute to asthma pathogenesis, montelukast is not a corticosteroid, making it an inadequate choice for managing an acute asthma attack in a patient on beta-blockers.

D. Oral corticosteroids: Oral corticosteroids are effective in managing asthma, but they require a considerable amount of time to achieve their therapeutic effects. For an acute asthma attack, an intravenous corticosteroid is required to provide rapid relief.

**Correct Answer Explanation:** In the context of an acute asthma attack in a patient on beta-blockers, an intravenous corticosteroid (such as methylprednisolone) is the correct choice due to its rapid onset of action and potent anti-inflammatory effects. Methylprednisolone suppresses inflammation, which is essential in the management of an acute asthma attack. The other options either have limited efficacy or are inappropriate for the specific situation presented.