Obstructive pulmonary diseases: The Daily PANCE Blueprint

The answer is C. Tiotropium

Tiotropium (Spiriva) is a long-acting muscarinic antagonist (LAMA) that works by blocking M3 muscarinic receptors in bronchial smooth muscle, leading to bronchodilation. Tiotropium has a duration of action of 24+ hours, allowing for once-daily dosing. It is primarily used in the management of COPD and can also be used as an add-on therapy for asthma. LAMAs like tiotropium reduce exacerbations and improve lung function by preventing acetylcholine-induced bronchoconstriction. Unlike short-acting agents, tiotropium’s slow dissociation rate from receptors contributes to its prolonged bronchodilator effect.

Incorrect Answer Explanations:

• A. Albuterol is a short-acting beta-2 agonist (SABA), not a LAMA. It works by stimulating beta-2 adrenergic receptors in bronchial smooth muscle, causing bronchodilation. Albuterol has a short duration of action (4-6 hours) and is primarily used for quick relief of bronchospasm.
• B. Ipratropium is a short-acting muscarinic antagonist (SAMA), not a LAMA. While it also blocks muscarinic receptors like tiotropium, it has a much shorter duration of action (6-8 hours) requiring multiple daily doses. It’s often used in combination with albuterol for COPD management.
• D. Salmeterol is a long-acting beta-2 agonist (LABA), not a LAMA. It stimulates beta-2 adrenergic receptors with a duration of action of 12 hours. It’s used as maintenance therapy for asthma and COPD, often in combination with inhaled corticosteroids.
• E. Montelukast is a leukotriene receptor antagonist (LTRA), not a LAMA. It blocks leukotriene receptors, reducing inflammation in the airways. It’s primarily used in asthma management, particularly for exercise-induced and allergic asthma, and has no direct bronchodilatory effects.