MEDizzy - A 44-year-old man presented to his physician complaining of

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Drugs for Bronchospastic Disorders

A 44-year-old man presented to his physician complaining of increasing cough producing yellow sputum and moderate shortness of breath on exertion. The man had a long history of heavy cigarette smoking and had suffered from an episode of sustained ventricular tachycardia 1 year ago. Physical examination showed a patient with shallow breathing and a barrel chest. Auscultation demonstrated wheezing and distant heart sounds. An inhalation therapy was prescribed. A drug with which of the following mechanisms of action would be most appropriate for this patient?

ExplanationThe patient’s history and symptoms indicate that he was most likely suffering from chronic obstructive pulmonary disease (COPD). Ipratropium is a first-line agent in COPD because its action in these patients is equal or superior to that achieved by β2 agonists. Ipratropium is a quaternary ammonium antimuscarinic drug. Unlike tertiary amines, quaternary ammonium antimuscarinic drugs mainly block muscarinic receptors but also have a significant blocking activity on nicotinic Nn receptors. Therefore, inhaled ipratropium can block both M3 receptors on bronchial smooth muscle and Nn receptors located in small parasympathetic ganglia within the bronchial tree. Both actions can contribute to the final bronchodilating effect of the drug.