What adverse effect should the nurse monitor for in a client prescribed both digoxin and furosemide?

When a client is prescribed both digoxin and furosemide, it is vital to monitor for digoxin toxicity primarily due to the potential for electrolyte imbalances, particularly hypokalemia. Furosemide, a loop diuretic, increases urinary output, which can lead to the loss of potassium. Low potassium levels can enhance the effects of digoxin, putting the patient at a higher risk for toxicity.

Digoxin is a medication that requires careful balance in serum potassium levels because it competes with potassium for binding at the same site on the sodium-potassium ATPase pump. When potassium levels are low, digoxin can effectively displace potassium, leading to increased cardiac effects, such as arrhythmias, nausea, vomiting, and even potentially life-threatening conditions.

Monitoring for digoxin toxicity becomes essential in this scenario because patient safety relies heavily on ensuring potassium levels remain within the normal range, ultimately preventing adverse cardiac events associated with increased digoxin levels in the presence of low serum potassium.