In patients receiving loop diuretics, what is a potential hemodynamic side effect to monitor for?

• A. Hypertension
• B. Hyperkalemia
• C. Tachycardia
• D. Orthostatic hypotension

Answer: (D)

Loop diuretics reduce intravascular volume by promoting sodium and water loss, which lowers preload and can drop blood pressure. The most important hemodynamic side effect to monitor is orthostatic hypotension—a drop in blood pressure with standing that can cause dizziness or faintness due to reduced cerebral perfusion from volume loss. Check blood pressure and heart rate in supine and after standing, and ask about dizziness when standing. Hypertension is not expected with these drugs; they tend to cause lower potassium (hypokalemia) rather than hyperkalemia; tachycardia can occur but isn’t as specific a signal as orthostatic hypotension.