A client who is beginning Lasix therapy: which laboratory value is priority to monitor?

A client who is beginning Lasix therapy: which laboratory value is priority to monitor?

• A. Sodium
• B. Potassium
• C. Calcium
• D. Magnesium

Answer: (B)

Loop diuretics like Lasix cause increased potassium loss in the distal tubule, so monitoring the potassium level is essential. Potassium is critical for maintaining cardiac electrical stability, and dropping levels can lead to dangerous arrhythmias and muscle weakness. While other electrolytes like sodium, calcium, and magnesium can be affected, the immediate and most dangerous risk with Lasix is hypokalemia, making potassium the priority lab to track. If potassium falls, treatment may include supplementation or adjusting the diuretic regimen with careful monitoring.

Loop diuretics like Lasix cause increased potassium loss in the distal tubule, so monitoring the potassium level is essential. Potassium is critical for maintaining cardiac electrical stability, and dropping levels can lead to dangerous arrhythmias and muscle weakness. While other electrolytes like sodium, calcium, and magnesium can be affected, the immediate and most dangerous risk with Lasix is hypokalemia, making potassium the priority lab to track. If potassium falls, treatment may include supplementation or adjusting the diuretic regimen with careful monitoring.