WBR0756
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| Author | [[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Yazan Daaboul, M.D.)]] |
|---|---|
| Exam Type | USMLE Step 1 |
| Main Category | Pharmacology |
| Sub Category | Pulmonology |
| Prompt | A 12-year-old boy is brought by his mother to the physician's office for occasional shortness of breath. The boy explains that whenever he is playing soccer with his friends, he becomes short of breath and can hear himself "whistling" during expiration. When asked, the patient denies any symptoms during normal, non-exertional activity. Following appropriate work-up, the physician prescribes inhaled albuterol and oral montelukast. What is the mechanism of action of montelukast? |
| Answer A | 5-lipooxygenase inhibitor |
| Answer A Explanation | Zileuton is a 5-lipooxygenase (5-LOX) inhibitor. |
| Answer B | Muscarinic receptor antagonist |
| Answer B Explanation | Ipratropium and tiotropium are short- and long-acting muscarinic receptor antagonists, respectively. |
| Answer C | Phosphodiesterase inhibitor |
| Answer C Explanation | Theophylline, a methylxanthine, is a non-specific phosphodiesterase inhibitor. |
| Answer D | Monoclonal IgE antibody |
| Answer D Explanation | Omalizumab is a monoclonal anti-IgE antibody that binds to free IgE antibodies. |
| Answer E | Leukotriene receptor antagonist |
| Answer E Explanation | Montelukast and zafirlukast are leukotriene receptor antagonists. |
| Right Answer | E |
| Explanation | The patient is presenting with signs and symptoms consistent with exercise-induced asthma. Antileukotrienes, such as montelukast and zafirlukast, are leukotriene receptor antagonists that have demonstrated efficacy among patients with exercise-induced asthma and aspirin-induced asthma. Educational Objective: Leukotriene receptor inhibitors, such as montelukast and zafirlukast, are indicated in exercise-induced asthma and aspirin-induced asthma. |
| Approved | Yes |
| Keyword | Montelukast, Zafirlukast, Asthma, Antileukotrienes, Leukotriene receptor antagonist, Exercise-induced asthma, Aspirin-induced asthma, Wheezing, Whistling, Albuterol, Pharmacotherapy, Drugs |
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