WBR0092
| Author | [[PageAuthor::Gonzalo Romero, reviewed by user: Jad Al Danaf]] |
|---|---|
| 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 presents to the emergency room with the chief complaint of persistent and painful erection of 5 hours duration. He is very concerned mainly due to the duration of the erection and the worsening penile pain. He usually has erections throughout the night and in the morning, but normally they last a couple of minutes. He denies any sexual encounter the previous night, and any erectile dysfunction for which he is taking any medication.
He has recently been prescribed a medication to help him sleep, which he has been taking for the last 6 weeks. He also has a history of depression for which he is also on medical therapy. His vitals are BP=126/70 mmHg, HR=87 and regular, RR=16, T=37 C. The medical team is concerned that the drug prescribed to the patient to help him sleep is associated with his prolonged painful erection. 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::The new drug that has been prescribed for the patient is most likely to be Trazodone. It is an atypical antidepressant that belongs to the serotonin antagonist and reuptake inhibitor (SARI) class of antidepressants. It is usually prescribed to treat insomnia in patients with major depressive symptoms, and has also been shown to have anxiolytic properties.]] |
| Answer B | AnswerB::Inhibits NE reuptake |
| Answer B Explanation | [[AnswerBExp::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::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::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. It might also cause an increase in appetite with possible weight gain.
Trazodone is thought to cause priapism through its antagonism on alpha adrenergic receptors, but this is not the mechanism of action of the drug; rather it is the suggested specific mechanism in causing priapism.]] |
| Answer E | AnswerE::modulating GABA receptors |
| Answer E Explanation | [[AnswerEExp::Different drugs act by increasing the opening of GABA channels such as benzodiazepines and barbiturates.]] |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::Trazadone is an atypical antidepressant used mainly to treat insomnia. With high doses it can be used to treat depression. An important but rare side effect is priapism, which is a painful sustained penile erection of more than 4 hours. It also causes sedation, nausea, and postural hypotension. It acts by inhibiting serotonin reuptake and belongs to the serotonin antagonist and reuptake inhibitor (SARI) class. Educational Objective: Trazadone is an atypical antidepressant, which is used to treat insomnia in patients with depression. Its mechanism of action is inhibiting serotonin reuptake and can cause priapism, on rare occasions, due to its possible antagonism on alpha adrenergic receptors. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::trazodone, WBRKeyword::priapism, WBRKeyword::depression, WBRKeyword::insomina, WBRKeyword::serotonin reuptake inhibitor |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
Image [[WBRImage::|]] Caption WBRImageCaption::no-display Position [[WBRImagePlace::Explanation|]]