Which adverse effect is specifically noted for Spironolactone?

Spironolactone is a potassium-sparing diuretic that is particularly known for its unique side effect of gynecomastia. This condition, characterized by the enlargement of breast tissue in males, occurs due to spironolactone's anti-androgenic properties, which can influence hormone levels. The drug functions as an aldosterone antagonist, affecting the hormonal balance in the body, leading to changes in estrogen and testosterone effects, which can manifest as gynecomastia.

The other options represent effects that can be associated with various medications or conditions but are not specifically noted for spironolactone. For instance, hypokalemia is more commonly linked with thiazide and loop diuretics rather than potassium-sparing agents like spironolactone. Nocturia and fatigue can be experienced in many individuals for various reasons and are not uniquely associated with spironolactone. Therefore, the acknowledgment of gynecomastia as a specific adverse effect of spironolactone highlights this medication's distinct profile among diuretics.