Proscar (finasteride) can cause gynecomastia
FDA officials are alerting health professionals that Proscar (finasteride) can cause gynecomastia.
Breast enlargement in men is the MOST frequent adverse effect of Proscar that's reported to the FDA. It's probably caused by an imbalance between the hormones testosterone and estrogen.
Gynecomastia is associated with many commonly-used drugs...digoxin...cimetidine...spironolactone...ketoconazole...and others.