Which statement best describes adverse effects of spironolactone compared with eplerenone?

• A. Spironolactone has fewer endocrine side effects.
• B. Eplerenone causes gynecomastia.
• C. Both spironolactone and eplerenone have identical side effect profiles.
• D. Spironolactone can cause hyperkalemia and antiandrogenic effects (gynaecomastia), while eplerenone has fewer endocrine side effects.

Answer: (D)

Spironolactone and eplerenone are both aldosterone antagonists used as potassium-sparing diuretics, but spironolactone is less selective and blocks other steroid receptors. This leads to endocrine-related side effects such as gynecomastia in men and menstrual irregularities in women, in addition to the risk of hyperkalemia. Eplerenone, being more selective for the mineralocorticoid receptor, has far fewer antiandrogenic/endocrine effects. So describing spironolactone as capable of hyperkalemia plus antiandrogenic effects (gynecomastia), with eplerenone having fewer endocrine side effects, captures the key difference between their adverse effect profiles. Hyperkalemia remains a risk with both, but the distinctive endocrine side effects are much more prominent with spironolactone.