WBR0092

Author	PageAuthor::Gonzalo Romero
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Behavioral Science/Psychiatry, MainCategory::Pharmacology
Sub Category	SubCategory::Neurology
Prompt	[[Prompt::A 35 year-old male comes to the emergency room for acute medical care due to a persistent erection, which he thought it would go away. He is very concerned because this erection has lasted more than 6 hours. He usually has erections throughout the night and in the morning, but normally last a couple of minute. He denies any sexual encounter the night before. The nurse practitioner meets the patient in the ER and starts asking health relevant questions. Upon interrogation, he states he has an intense pain over his penis. He recently was prescribed a medication to aid with sleep, which he has been taking for the last 6 weeks. He has a history of depression. His vitals are BP=126/70 mmHg, HR=87, RR=16, T=37 C. The nurse practitioner communicates the information to the medical team. They team is concerned that the drug prescribed to this patient to “aid with his sleep” is associated with his symptoms. Which of the following is the mechanism of action of the drug most likely prescribed to this patient?]]
Answer A	AnswerA::Inhibits serotonin reuptake
Answer A Explanation	AnswerAExp::Correct
Answer B	AnswerB::Inhibits NE reuptake
Answer B Explanation	AnswerBExp::B. Maprotiline is an atypical antidepressant which acts by blocking NE reuptake. It can cause sedation as a side effect.
Answer C	AnswerC::Serotonin receptor agonist
Answer C Explanation	AnswerCExp::C. Buspirone used to treat general anxiety disorder, acts by stimulating setononin (5-HT1a) receptors. It does not cause sedation, addiction or tolerance.
Answer D	AnswerD::Alpha-2 receptor antagonist
Answer D Explanation	[[AnswerDExp::D. Mirtazapine is an atypical antidepressant, which acts blocking the alpha-2 receptors in the presynaptic neurons increasing the release of NE and serotonin. It causes sedation; therefore it can be used in depressed patients with insomnia. Also causes an increase in the appetite leading to weight gain (this could be beneficial in elderly or anorexic patients).]]
Answer E	AnswerE::GABA receptor moduling
Answer E Explanation	AnswerEExp::E. Different drugs act by increasing the opening of GABA channels such as benzodiazepines and barbiturates.
Right Answer	RightAnswer::A
Explanation	[[Explanation::Trazadone [1] is an atypical antidepressant used mainly to treat insomnia. With high doses it can be used to treat depression. An important side effect is priapism, which is a painful sustained penile erection. It also causes sedation, nausea, and postural hypotension. It acts by inhibiting serotonin reuptake primarily Educational objective: Trazadone is an atypical antidepressant, which is used to treat insomnia. It acts by inhibiting serotonin reuptake primarily. Its typical side effect is priapism Tags: #Pharmacology #Psychiatry References: First Aid 2013 page 476 Educational Objective: References: ]]
Approved	Approved::Yes
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