What is a major adverse effect of spironolactone (Aldactone)?

Spironolactone, a potassium-sparing diuretic, primarily works by antagonizing the action of aldosterone in the kidneys, which leads to increased sodium and water excretion while conserving potassium. Given this mechanism of action, one of the major adverse effects associated with spironolactone is hyperkalemia.

Hyperkalemia occurs because spironolactone prevents the loss of potassium, resulting in elevated levels of potassium in the blood. This can lead to serious complications, such as cardiac arrhythmias, if not monitored and managed properly. Monitoring potassium levels is critical in patients receiving spironolactone to prevent this potentially life-threatening condition.

In contrast, other options like hypokalemia and dehydration are unlikely with spironolactone use, as it specifically aims to retain potassium. While hypotension can occur in some cases due to the diuretic effect, it is not as directly associated with spironolactone as hyperkalemia is. Thus, hyperkalemia stands out as a significant risk associated with the use of this medication.