WBR0756

Author	[[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Yazan Daaboul, M.D.)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pharmacology
Sub Category	SubCategory::Pulmonology
Prompt	[[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	AnswerA::5-lipooxygenase inhibitor
Answer A Explanation	AnswerAExp::Zileuton is a 5-lipooxygenase (5-LOX) 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::Monoclonal IgE antibody
Answer D Explanation	AnswerDExp::Omalizumab is a monoclonal anti-IgE antibody that binds to free 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, 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. References: First Aid 2014 page 614]]
Approved	Approved::Yes
Keyword	WBRKeyword::Montelukast, WBRKeyword::Zafirlukast, WBRKeyword::Asthma, WBRKeyword::Antileukotrienes, WBRKeyword::Leukotriene receptor antagonist, WBRKeyword::Exercise-induced asthma, WBRKeyword::Aspirin-induced asthma, WBRKeyword::Wheezing, WBRKeyword::Whistling, WBRKeyword::Albuterol, WBRKeyword::Pharmacotherapy, WBRKeyword::Drugs
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::