Which cardiac medication is known to cause gynecomastia as a side effect?

• A. Enalapril
• B. Spironolactone
• C. Metoprolol
• D. Furosemide

Answer: (B)

Gynecomastia from medications often comes from drugs with antiandrogen effects. Spironolactone is a steroidal mineralocorticoid receptor antagonist used as a potassium-sparing diuretic; beyond blocking aldosterone, it can bind and inhibit androgen receptors and reduce testosterone activity. This antiandrogen action shifts the hormonal balance toward estrogen effects in breast tissue, promoting proliferation of gynecomastia, especially with longer use or higher doses.

The other options don’t have this antiandrogen profile. Enalapril is an ACE inhibitor with effects like cough or hyperkalemia but not gynecomastia. Metoprolol is a beta-blocker and can cause sexual side effects, but gynecomastia is not characteristic. Furosemide is a loop diuretic and not associated with breast tissue changes.