WBR0093

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 75-year-old diabetic woman complains of worsening pain in her feet. The pain started almost 7 months ago and has been increasing in severity lately. The pain is localized in both feet, non-radiating and burning in nature. The patient admits that she has not been compliant with her diabetes medication. Her vitals are blood pressure of 125/80 mmHg, heart rate of 70 beats/minute, temperature of 37 C and respiratory rate of 16 per minute. On physical exam, the patient has decreased sensation in the right and left legs below the knees and decreased Achilles tendon reflexes bilaterally. Laboratory tests reveal an HbA1c level of 15 mg/dL. The patient is educated about the important of adherence to diabetes medication and lifestyle changes to herald the progression of the different complications of diabetes. The physician also considers the prescription of duloxetine to relive the patient’s symptoms of pain in the feet. Which of the following is the mechanism of action of this drug?]]
Answer A	AnswerA::Inhibits specifically serotonin reuptake
Answer A Explanation	[[AnswerAExp::SSRIs specifically inhibit 5-HT reuptake. Examples are paroxetine, sertraline, citalopram and sertraline. They are used for depression, general anxiety disorder, bulimia bulimia, social phobias, OCD and PTSD. Their side effects are sexual dysfunction, GI distress. In excess they can cause serotonin syndrome if used in combination with drugs that increase Serotonin (confusion, hyperthermia, myoclonus, flushing, diarrhea and cardiovascular collapse).]]
Answer B	AnswerB::Inhibits serotonin and NE reuptake
Answer B Explanation	[[AnswerBExp::Venlaxafine has the same mechanism of action and is used for general anxiety disorder and panic disorders.]]
Answer C	AnswerC::Inhibits serotonin, NE and Dopamine metabolism
Answer C Explanation	[[AnswerCExp::MAO (monoamine oxidase) inhibitors increase the levels of NE, 5-HT and DA. They include drugs like: phenelzine, isocarboxacid, selegiline (selective MAO-B inhibitor). They are used mainly for atypical depression. Its major side effects are hypertensive crisis when combined with tyramine, a compound found in cheese and wine.]]
Answer D	AnswerD::Alpha-2 receptor antagonist
Answer D Explanation	AnswerDExp::Mirtazapine is an alpha-2 receptor antagonist. It is an atypical antidepressant which causes appetite increase and weight gain, therefore useful in the elderly and anorexic patients.
Answer E	AnswerE::Alpha-2 receptor agonist
Answer E Explanation	[[AnswerEExp::Methyldopa and clonidine are selective for α2-adrenergic agonists. Methyldopa is used to treat hypertension, especially in pregnant women. Clonidine can be used for hypertension, anxiety/panic disorder, and certain pain conditions.]]
Right Answer	RightAnswer::B
Explanation	[[Explanation::This patient is presenting with periphery diabetic neuropathy, therefore is prescribed duloxetine, which is a serotonin–norepinephrine reuptake inhibitor (SNRI). It inhibits NE and 5-HT reuptake. It has greater effect on NE. Its side effects are hypertension, sedation, nausea and stimulant effects. Wiki-Mnemonics: Duloxetine and velafaxine are DOBLE HITTERS = inhibit both NE and serotonin reuptake DUALxetine = dual mechanism of action (inhibit both NE and serotonin reuptake) Educational Objective: # Duloxetine is an atypical antidepressant, which can be used for peripheral diabetic neuropathy. It inhibits both NE and 5-HT reuptake, having a dual mechanism of action. Venlaxafine has the same mechanism of action as duloxetine. References: First Aid 2013 page 472-476]]
Approved	Approved::Yes
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