A 68-year-old woman visits the office because she experiences frequent syncopal attacks. The most recent occurrence happened three days ago while she was making her way to her car and lasted roughly one minute. Even though she was exhausted, she was able to return to her regular activities after that. She had no previous heart palpitations or chest pain. The patient has experienced frequent episodes of intermittent dizziness as well as two similar syncopal episodes in the last two months. Chronic renal disease and hypertension are among the past medical conditions. She regularly takes clonidine, amlodipine, and lisinopril. Pulse rate is 44/min and blood pressure is 155/85 mm Hg. Lung and heart sounds are typical. She stops having syncopal episodes once the offending medication is stopped. The drug responsible for this patient's episodes most likely functions through which of the following mechanisms?

Question

A 68-year-old woman visits the office because she experiences frequent syncopal attacks. The most recent occurrence happened three days ago while she was making her way to her car and lasted roughly one minute. Even though she was exhausted, she was able to return to her regular activities after that. She had no previous heart palpitations or chest pain. The patient has experienced frequent episodes of intermittent dizziness as well as two similar syncopal episodes in the last two months. Chronic renal disease and hypertension are among the past medical conditions. She regularly takes clonidine, amlodipine, and lisinopril. Pulse rate is 44/min and blood pressure is 155/85 mm Hg. Lung and heart sounds are typical. She stops having syncopal episodes once the offending medication is stopped.   The drug responsible for this patient's episodes most likely functions through which of the following mechanisms?

Quizplus · Accepted Answer

Eductional Objective: An antihypertensive drug called clonidine activates central alpha-2 adrenergic receptors, which results in less norepinephrine being released presynaptically and less sympathetic outflow. This can result in orthostatic syncope by preventing the normal baroceptor-mediated rise in peripheral vascular resistance and heart rate during standing.

A 68-Year-Old Woman Visits the Office Because She Experiences Frequent