WBR0756

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
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 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. Educational Objective: References: ]]
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::