Loop diuretics commonly cause which electrolyte disturbance that predisposes to arrhythmias?

Loop diuretics commonly cause which electrolyte disturbance that predisposes to arrhythmias?

• A. Hyperkalemia
• B. Hypokalemia
• C. Hyponatremia
• D. Hypercalcemia

Answer: (B)

Loop diuretics block the NKCC2 transporter in the thick ascending limb, so more sodium is delivered to the distal nephron and potassium is lost in the urine. This leads to low serum potassium—hypokalemia. Potassium is crucial for setting the resting membrane potential and repolarization of cardiac cells; when potassium is low, repolarization is prolonged and electrical instability increases, raising the risk of arrhythmias. So the electrolyte disturbance that most commonly links loop diuretics to arrhythmias is hypokalemia. While other disturbances can occur, hypokalemia best explains the arrhythmia risk with these drugs.

Loop diuretics block the NKCC2 transporter in the thick ascending limb, so more sodium is delivered to the distal nephron and potassium is lost in the urine. This leads to low serum potassium—hypokalemia. Potassium is crucial for setting the resting membrane potential and repolarization of cardiac cells; when potassium is low, repolarization is prolonged and electrical instability increases, raising the risk of arrhythmias. So the electrolyte disturbance that most commonly links loop diuretics to arrhythmias is hypokalemia. While other disturbances can occur, hypokalemia best explains the arrhythmia risk with these drugs.