Which of the following are the main disadvantages of norepinephrine?

• A. Reduced organ perfusion due to intense vasoconstriction; Myocardial ischemia due to increased afterload and HR; Pulmonary vasoconstriction and increased PVR
• B. Increased renal perfusion and urine output
• C. Decreased myocardial oxygen demand
• D. No significant disadvantages

Answer: (A)

Norepinephrine carries notable drawbacks because its strong alpha-adrenergic vasoconstriction and beta-1 cardiac stimulation raise arterial pressure but can compromise tissue perfusion and increase cardiac workload. The intense vasoconstriction increases systemic vascular resistance, which can shunt blood away from nonessential organs and reduce perfusion to areas like the gut, kidneys, and skin. Its beta-1 effects elevate heart rate and contractility, driving up myocardial oxygen demand; in patients with coronary disease or limited oxygen supply, this can precipitate myocardial ischemia. It can also cause constriction in the pulmonary vasculature, increasing pulmonary vascular resistance and potentially stressing the right heart and worsening gas exchange. By contrast, increased renal perfusion or urine output is not a typical outcome; norepinephrine often reduces renal blood flow via vasoconstriction. It does not decrease myocardial oxygen demand, and there are clear disadvantages to its use when high-dose vasoconstriction or poor perfusion risk ischemia.