WBR0756
| Author | [[PageAuthor::Rim Halaby, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pharmacology |
| Sub Category | |
| Prompt | [[Prompt::A 12 year old boy is brought by his mother to the physician's office for shortness of breath during exercise. The boy explains that whenever he is playing football with his friends, he becomes unable to take a breath and hears a whistling sound with every breath. When asked, the patient denies any symptoms during normal activity. Following appropriate work-up, the physician prescribes inhaled albuterol and montelukast. What is the most likely mechanism of action of montelukast?]] |
| Answer A | AnswerA::5-lipooxygenase inhibitor |
| Answer A Explanation | AnswerAExp::Zileuton is a 5-lipooxygenase inhibitor |
| Answer B | AnswerB::Muscarinic receptor antagonist |
| Answer B Explanation | AnswerBExp::Ipratropium and tiotropium are short and long acting muscarinic receptor antagonists, respectively. |
| Answer C | AnswerC::Phosphodiesterase inhibitor |
| Answer C Explanation | AnswerCExp::Theophylline, a methylxanthine, is a non-specific phosphodiesterase inhibitor. |
| Answer D | AnswerD::IgE antibody binder |
| Answer D Explanation | AnswerDExp::Omalizumab is a monoclonal anti-IgE antibody that binds to unbound serum IgE antibodies. |
| Answer E | AnswerE::Leukotriene receptor antagonist |
| Answer E Explanation | AnswerEExp::Montelukast and zafirlukast are leukotriene receptor antagonists. |
| Right Answer | RightAnswer::E |
| Explanation | [[Explanation::The patient is presenting with signs and symptoms consistent with exercise-induced asthma. Antileukotrienes, like montelukast and zafirlukast, are leukotriene receptor antagonists, that have been shown to be particularly effective for exercise-induced asthma and for aspirin-induced asthma.
Educational Objective:
Leukotriene receptor inhibitors, like montelukast and zafirlukast, are effective for exercise-induced asthma. |
| Approved | Approved::No |
| Keyword | WBRKeyword::montelukast, WBRKeyword::zafirlukast, WBRKeyword::lipooxygenase, WBRKeyword::lipoxygenase, WBRKeyword::receptor, WBRKeyword::antagonist, WBRKeyword::inhibitor, WBRKeyword::blocker, WBRKeyword::antagonists, WBRKeyword::inhibitors, WBRKeyword::blockers, WBRKeyword::block, WBRKeyword::pathway, WBRKeyword::asthma, WBRKeyword::exercise-induced, WBRKeyword::exercise, WBRKeyword::induced |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |