Does Lasix (furosemide) cause gynecomastia?

Does Lasix (Furosemide) Cause Gynecomastia?

Lasix (furosemide) is not commonly associated with gynecomastia, and there is limited evidence supporting a causal relationship between furosemide use and gynecomastia. While there have been isolated case reports suggesting a possible connection, furosemide is not listed among medications with strong evidence for causing gynecomastia in clinical guidelines.

Evidence Assessment

Medications Known to Cause Gynecomastia

Medications with strong evidence for causing gynecomastia include:

• Spironolactone (an aldosterone antagonist diuretic) is well-documented to cause gynecomastia 1, 2
• 5-α reductase inhibitors (finasteride, dutasteride) 2
• Estrogens and medications with estrogenic effects 3
• Anti-androgens and GnRH analogs 3
• Ketoconazole 3

Furosemide and Gynecomastia

• The 2018 ACC/AHA hypertension guidelines do not list gynecomastia as a side effect of loop diuretics like furosemide 1
• In contrast, the same guidelines specifically mention that spironolactone is "associated with greater risk of gynecomastia and impotence as compared with eplerenone" 1
• There is one case report suggesting gynecomastia potentially resulting from co-administration of furosemide with digoxin, but this was rated only as a "possible" drug interaction rather than a confirmed causal relationship 4

Clinical Implications

Management of Diuretic-Induced Gynecomastia

If a patient develops gynecomastia while taking diuretics:

1. Consider alternative medications:

   • For patients requiring a potassium-sparing diuretic who develop gynecomastia on spironolactone, eplerenone is recommended as it has less anti-androgenic effects 1, 2
   • For patients with cirrhosis-related ascites who develop gynecomastia on spironolactone, amiloride (10-40 mg/day) can be substituted 1, 2

2. Evaluate for other causes:

   • Gynecomastia results from conditions causing an imbalance of estrogenic and androgenic effects on breast tissue 4
   • Consider other medications, underlying conditions (cirrhosis, hypogonadism, renal insufficiency), or supplements 5

Diagnosis and Assessment

• True gynecomastia is defined as glandular breast tissue enlargement, presenting as a disc-like area of breast tissue under the nipple 2
• Pseudogynecomastia (fatty tissue deposition without glandular proliferation) is common in patients with elevated BMI 2
• Most cases can be diagnosed based on clinical findings without imaging 2

Conclusion

While furosemide has been mentioned in some case reports in connection with gynecomastia, the evidence is limited and inconsistent. Spironolactone is the diuretic most strongly associated with gynecomastia based on current clinical guidelines. If gynecomastia develops in a patient taking furosemide, consider other potential causes or contributing medications before attributing it to furosemide alone.

For patients with diuretic-induced gynecomastia, treatment options include discontinuation of the offending medication when possible, switching to alternative medications with lower risk of gynecomastia, and in persistent cases, consideration of medical therapy or surgical intervention.