Spironolactone-Induced Unilateral Gynecomastia

Area of Science:

• Endocrinology
• Pharmacology
• Internal Medicine

Background:

• Gynecomastia, a benign enlargement of male breast tissue, affects a significant portion of the male population.
• Drug-induced gynecomastia accounts for approximately 25% of all cases, highlighting the importance of medication review.
• Spironolactone, a potassium-sparing diuretic, is known to cause gynecomastia, though typically bilateral.

Observation:

• A 52-year-old male patient developed unilateral, painful right breast swelling after 12 months of spironolactone treatment for hypokalemia.
• The patient was initially treated with hydrochlorothiazide for hypertension, which was later replaced by spironolactone.
• Symptomatic improvement in hypokalemia was noted after spironolactone initiation, preceding the onset of gynecomastia.

Findings:

• Discontinuation of spironolactone led to the resolution of breast pain and a decrease in swelling within one month.
• This case presents a rare instance of unilateral gynecomastia attributed to spironolactone.
• Literature review primarily documents bilateral gynecomastia associated with spironolactone use.

Implications:

• Clinicians should consider drug-induced etiology, specifically spironolactone, when encountering unilateral gynecomastia.
• Educating patients about the potential for drug-induced gynecomastia is crucial during prescription.
• Eplerenone may serve as a safer alternative medication for patients susceptible to spironolactone-induced gynecomastia.