Which medication class is commonly used for acute allergic reactions causing bronchospasm?

• A. Short-acting beta-agonists (SABA), e.g., albuterol.
• B. Long-acting muscarinic antagonists.
• C. Systemic corticosteroids.
• D. Antihistamines.

Answer: (A)

When allergic reactions trigger bronchospasm, the immediate goal is rapid relief of airway constriction. Short-acting beta-agonists provide quick bronchodilation by activating beta-2 receptors on bronchial smooth muscle. This activates a signaling cascade that increases cAMP, lowers intracellular calcium, and relaxes the smooth muscle, opening the airways within minutes. Inhaled delivery targets the lungs for fast effect with fewer systemic downsides, making these agents the go-to rescue therapy for acute bronchospasm.

Other options don’t fit as well for rapid relief. Long-acting muscarinic antagonists aren’t used for immediate bronchospasm because their effects are slower and they’re intended for maintenance rather than rescue. Systemic corticosteroids reduce inflammation but take hours to days to work, so they’re not for instant relief. Antihistamines help with nasal and cutaneous allergy symptoms but don’t provide rapid bronchodilation.